Directory structure:
└── Лаб1/
    ├── README.md
    ├── index.html
    ├── LICENSE
    ├── script.js
    ├── tasks.md
    └── docs/
        ├── requirements.md
        └── task.md

================================================
FILE: README.md
================================================
# Web Programming: Lab 1

This is a client-side web app that checks if a given 2D point (X, Y) falls inside a specific graphed area based on a given radius (R).

## Functions
You basically pick your coordinates, set a radius, and hit submit. The app calculates whether your point landed directly inside the colored shapes on the graph or missed them entirely.

## How to Run It
1. Download the files.
2. Double-click `index.html` to open it in your browser.
3. That's pretty much it.

## Project Structure
- `index.html` — The main layout holding the UI and embedded CSS styled.
- `script.js` — Vanilla JavaScript: Canvas rendering, math checking, and validations.
- `assets/` — Try to guess.
- `docs/` — Assignment instructions.



================================================
FILE: index.html
================================================
<!DOCTYPE html>
<html lang="ru">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Лабораторная работа №1</title>
    <style>

        body {
            font-family: Arial, sans-serif;
            background-color: #ffffff;
            color: #000000;
            padding: 20px;
            margin: 0;
        }

        #layout-table {
            width: 800px;
            margin: 0 auto;
            border-collapse: collapse;
        }

        table, th, td {
            border: 1px solid #000000;
        }

        #header {
            background-color: #eeeeee;
            color: #000000; /* Каскадирование */
            padding: 10px;
            text-align: center;
            font-family: monospace;
            font-size: 16px;
        }

        #header span.variant {
            font-weight: bold;
            color: #cc0000;
        }

        .content-cell {
            padding: 15px;
            vertical-align: top;
            width: 50%;
        }

        #point-form > .form-group {
            margin-bottom: 20px;
            padding: 10px;
            border: 1px dashed #aaaaaa;
        }

        .checkbox-group label {
            margin-right: 15px;
        }

        #point-form input[type="text"] {
            margin-left: 10px;
            padding: 4px;
            width: 120px;
        }

        .r-button {
            margin-right: 10px;
            padding: 5px 10px;
            background-color: #dddddd;
            border: 1px solid #888888;
            cursor: pointer;
        }

        .r-button.active {
            background-color: #888888;
            color: #ffffff;
        }

        #submit-btn {
            margin-top: 15px;
            padding: 8px 16px;
            cursor: pointer;
        }

        #clear-history-btn {
            padding: 5px 10px;
            margin-bottom: 10px;
            cursor: pointer;
        }

        .error {
            color: red;
            font-size: 12px;
            display: block;
            margin-top: 5px;
        }

        .global-error {
            color: red;
            font-weight: bold;
            margin-bottom: 10px;
        }

        .table-scroll-container {
            max-height: 250px;
            overflow-y: scroll;
        }

        #results-table th {
            background-color: #eeeeee;
            padding: 8px;
        }

        #results-table td {
            padding: 8px;
            text-align: center;
        }

        .canvas-container {
            text-align: center;
        }

        #oscar-easter-egg {
            position: fixed;
            bottom: -350px;
            left: 0;
            max-width: 250px;
            z-index: 9999;
            transition: bottom 0.25s linear;
        }
        #oscar-easter-egg.show {
            bottom: 0;
        }
    </style>
</head>
<body>

<table id="layout-table">
    <tr>
        <td colspan="2" id="header">
            <span>ФИО: <b>Кливцов Александр Александрович</b></span> |
            <span>Группа: <b>P3215</b></span> |
            <span class="variant">Вариант: 12729</span>
        </td>
    </tr>
    <tr>
        <td class="content-cell canvas-container">
            <h3>Область графика</h3>
            <canvas id="graphCanvas" width="300" height="300"></canvas>
            <p style="font-size: 12px;">(Точки отображаются относительно выбранного R)</p>
        </td>
        <td class="content-cell">
            <h3>Форма проверки</h3>
            <form id="point-form">

                <div class="global-error" id="global-error"></div>

                <div class="form-group" id="x-group">
                    <label><b>Изменение X (выберите хотя бы один):</b></label><br>
                    <div class="checkbox-group" style="margin-top: 10px;">
                        <label><input type="checkbox" name="xval" value="-2"> -2</label>
                        <label><input type="checkbox" name="xval" value="-1.5"> -1.5</label>
                        <label><input type="checkbox" name="xval" value="-1"> -1</label>
                        <label><input type="checkbox" name="xval" value="-0.5"> -0.5</label>
                        <label><input type="checkbox" name="xval" value="0"> 0</label><br>
                        <label><input type="checkbox" name="xval" value="0.5"> 0.5</label>
                        <label><input type="checkbox" name="xval" value="1"> 1</label>
                        <label><input type="checkbox" name="xval" value="1.5"> 1.5</label>
                        <label><input type="checkbox" name="xval" value="2"> 2</label>
                    </div>
                </div>

                <div class="form-group" id="y-group">
                    <label for="y-input"><b>Изменение Y:</b></label>
                    <input type="text" id="y-input" name="yval" placeholder="-3 ... 5">
                    <span class="error" id="y-error"></span>
                </div>

                <div class="form-group" id="r-group">
                    <label><b>Изменение R:</b></label><br>
                    <button type="button" class="r-button" data-val="1">1</button>
                    <button type="button" class="r-button" data-val="2">2</button>
                    <button type="button" class="r-button" data-val="3">3</button>
                    <button type="button" class="r-button" data-val="4">4</button>
                    <button type="button" class="r-button" data-val="5">5</button>
                    <input type="hidden" id="r-hidden" name="rval" value="">
                    <span class="error" id="r-error"></span>
                </div>

                <button type="submit" id="submit-btn" disabled>Проверить попадание</button>
            </form>
        </td>
    </tr>
    <tr>
        <td colspan="2" class="content-cell">
            <h3>История проверок</h3>
            <button type="button" id="clear-history-btn">Очистить историю</button>

            <div class="table-scroll-container">
                <table id="results-table">
                    <thead>
                        <tr>
                            <th>X</th>
                            <th>Y</th>
                            <th>R</th>
                            <th>Результат</th>
                            <th>Дата и время</th>
                        </tr>
                    </thead>
                    <tbody id="results-body">
                        <!-- Данные из LocalStorage -->
                    </tbody>
                </table>
            </div>
        </td>
    </tr>
</table>

<img id="oscar-easter-egg" src="assets/oscar.png" alt="Toasty">
<script src="script.js"></script>
<script src="https://cdn.jsdelivr.net/npm/yopta-script@latest/yopta.min.js"></script>
<script src="script.ys" type="text/yopta"></script>
</body>
</html>



================================================
FILE: LICENSE
================================================
GNU GENERAL PUBLIC LICENSE
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If conditions are imposed on you (whether by court order, agreement or otherwise) that contradict the conditions of this License, they do not excuse you from the conditions of this License. If you cannot convey a covered work so as to satisfy simultaneously your obligations under this License and any other pertinent obligations, then as a consequence you may not convey it at all. For example, if you agree to terms that obligate you to collect a royalty for further conveying from those to whom you convey the Program, the only way you could satisfy both those terms and this License would be to refrain entirely from conveying the Program.

13. Use with the GNU Affero General Public License.
Notwithstanding any other provision of this License, you have permission to link or combine any covered work with a work licensed under version 3 of the GNU Affero General Public License into a single combined work, and to convey the resulting work. The terms of this License will continue to apply to the part which is the covered work, but the special requirements of the GNU Affero General Public License, section 13, concerning interaction through a network will apply to the combination as such.

14. Revised Versions of this License.
The Free Software Foundation may publish revised and/or new versions of the GNU General Public License from time to time. Such new versions will be similar in spirit to the present version, but may differ in detail to address new problems or concerns.

Each version is given a distinguishing version number. If the Program specifies that a certain numbered version of the GNU General Public License “or any later version” applies to it, you have the option of following the terms and conditions either of that numbered version or of any later version published by the Free Software Foundation. If the Program does not specify a version number of the GNU General Public License, you may choose any version ever published by the Free Software Foundation.

If the Program specifies that a proxy can decide which future versions of the GNU General Public License can be used, that proxy's public statement of acceptance of a version permanently authorizes you to choose that version for the Program.

Later license versions may give you additional or different permissions. However, no additional obligations are imposed on any author or copyright holder as a result of your choosing to follow a later version.

15. Disclaimer of Warranty.
THERE IS NO WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY APPLICABLE LAW. EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM “AS IS” WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE PROGRAM IS WITH YOU. SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING, REPAIR OR CORRECTION.

16. Limitation of Liability.
IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MODIFIES AND/OR CONVEYS THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.

17. Interpretation of Sections 15 and 16.
If the disclaimer of warranty and limitation of liability provided above cannot be given local legal effect according to their terms, reviewing courts shall apply local law that most closely approximates an absolute waiver of all civil liability in connection with the Program, unless a warranty or assumption of liability accompanies a copy of the Program in return for a fee.

END OF TERMS AND CONDITIONS

How to Apply These Terms to Your New Programs

If you develop a new program, and you want it to be of the greatest possible use to the public, the best way to achieve this is to make it free software which everyone can redistribute and change under these terms.

To do so, attach the following notices to the program. It is safest to attach them to the start of each source file to most effectively state the exclusion of warranty; and each file should have at least the “copyright” line and a pointer to where the full notice is found.

     Web-Lab-1
     Copyright (C) 2026  Aklivtsov

     This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

     This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more details.

     You should have received a copy of the GNU General Public License along with this program.  If not, see <https://www.gnu.org/licenses/>.

Also add information on how to contact you by electronic and paper mail.

If the program does terminal interaction, make it output a short notice like this when it starts in an interactive mode:

     Web-Lab-1  Copyright (C) 2026  Aklivtsov
     This program comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
     This is free software, and you are welcome to redistribute it under certain conditions; type `show c' for details.

The hypothetical commands `show w' and `show c' should show the appropriate parts of the General Public License. Of course, your program's commands might be different; for a GUI interface, you would use an “about box”.

You should also get your employer (if you work as a programmer) or school, if any, to sign a “copyright disclaimer” for the program, if necessary. For more information on this, and how to apply and follow the GNU GPL, see <https://www.gnu.org/licenses/>.

The GNU General Public License does not permit incorporating your program into proprietary programs. If your program is a subroutine library, you may consider it more useful to permit linking proprietary applications with the library. If this is what you want to do, use the GNU Lesser General Public License instead of this License. But first, please read <https://www.gnu.org/philosophy/why-not-lgpl.html>.



================================================
FILE: script.js
================================================
const canvas = document.getElementById('graphCanvas');
const ctx = canvas.getContext('2d');
const width = canvas.width;
const height = canvas.height;
const center = width / 2; // середина — точка (0,0) (150px)
const R_PIXELS = 100;     // Длина R в пикселях на канвасе для отрисовки

// Элементы формы
const form = document.getElementById('point-form');
const yInput = document.getElementById('y-input');
const yError = document.getElementById('y-error');
const rHidden = document.getElementById('r-hidden');
const rError = document.getElementById('r-error');
const rButtons = document.querySelectorAll('.r-button');
const checkboxes = document.querySelectorAll('input[name="xval"]');
const submitBtn = document.getElementById('submit-btn');
const globalError = document.getElementById('global-error');
const resultsBody = document.getElementById('results-body');
const clearHistoryBtn = document.getElementById('clear-history-btn');

// Б - безопасность
const STORAGE_KEY = 'web_lab1_history';
let history = [];
let currentR = null;

try {
    const rawData = JSON.parse(localStorage.getItem(STORAGE_KEY));
    if (Array.isArray(rawData)) {
        // Проверяем LocalStorage (вдруг врёт)
        history = rawData.filter(rec => {
            if (typeof rec !== 'object' || rec === null) return false;
            if (![1, 2, 3, 4, 5].includes(rec.r)) return false;
            if (![-2, -1.5, -1, -0.5, 0, 0.5, 1, 1.5, 2].includes(rec.x)) return false;
            if (typeof rec.y !== 'number' || isNaN(rec.y) || ((rec.y < -3 || rec.y > 5) && rec.y !== 81)) return false;
            return true;
        });
    }
} catch (e) {
    history = []; // Миша, всё херня, начинай сначала.
}

// Пошло поехало
window.addEventListener('DOMContentLoaded', () => {
    // Очистка истории
    if (clearHistoryBtn) {
        clearHistoryBtn.addEventListener('click', () => {
            history = [];
            localStorage.removeItem(STORAGE_KEY);
            renderHistory();
            drawGraph();
        });
    }
    renderHistory();
    drawGraph();
    validateForm();
});

rButtons.forEach(btn => {
    btn.addEventListener('click', () => {
        rButtons.forEach(b => b.classList.remove('active'));
        btn.classList.add('active');
        rHidden.value = btn.getAttribute('data-val');
        currentR = parseFloat(rHidden.value);
        rError.textContent = '';
        validateForm();
        drawGraph();
    });
});

checkboxes.forEach(cb => {
    cb.addEventListener('change', validateForm);
});

yInput.addEventListener('input', () => {
    validateY();
    validateForm();
});

function checkHit(x, y, r) {
    // Первая четверть (X >= 0, Y >= 0): Четверть круга (R)
    if (x >= 0 && y >= 0) {
        return (x * x + y * y) <= (r * r);
    }
    // Вторая четверть (X <= 0, Y >= 0): Прямоугольник (ширина R, высота R/2)
    if (x <= 0 && y >= 0) {
        return x >= -r && y <= (r / 2);
    }
    // Третья четверть (X <= 0, Y <= 0): Пустота
    if (x <= 0 && y <= 0) {
        return false;
    }
    // Четвертая четверть (X >= 0, Y <= 0): Треугольник (проходит через (R, 0) и (0, -R/2))
    // Уравнение прямой: y = x/2 - r/2 => точка внутри если y >= x/2 - r/2
    if (x >= 0 && y <= 0) {
        return y >= (x / 2) - (r / 2);
    }
    return false;
}

function validateY() {
    const valStr = yInput.value.trim().replace(',', '.');
    if (valStr === '') {
        yError.textContent = 'Поле Y обязательно к заполнению.';
        return false;
    }

    const y = Number(valStr);
    if (isNaN(y)) {
        yError.textContent = 'Y должно быть числом (буквы недопустимы).';
        return false;
    }

    if ((y < -3 || y > 5) && y !== 81) {
        yError.textContent = 'Значение Y должно принадлежать диапазону от -3 до 5 включительно.';
        return false;
    }

    yError.textContent = '';
    return true;
}

function validateForm() {
    let isValid = true;

    if (!validateY()) isValid = false;

    const validRValues = [1, 2, 3, 4, 5];
    if (!rHidden.value) {
        rError.textContent = 'Необходимо выбрать значение R.';
        isValid = false;
    } else if (!validRValues.includes(parseFloat(rHidden.value))) {
        rError.textContent = 'Обнаружена подмена значения R!';
        isValid = false;
    } else {
        rError.textContent = '';
    }

    const validXValues = [-2, -1.5, -1, -0.5, 0, 0.5, 1, 1.5, 2];
    let xChecked = false;
    let xSpoofed = false;

    checkboxes.forEach(cb => {
        if (cb.checked) {
            xChecked = true;
            if (!validXValues.includes(parseFloat(cb.value))) {
                xSpoofed = true;
            }
        }
    });

    if (!xChecked) {
        globalError.textContent = 'Выберите хотя бы одно значение X.';
        isValid = false;
    } else if (xSpoofed) {
        globalError.textContent = 'Ошибка: передано недопустимое значение X!';
        isValid = false;
    } else {
        globalError.textContent = '';
    }

    submitBtn.disabled = !isValid;
    return isValid;
}

form.addEventListener('submit', (e) => {
    e.preventDefault();

    if (!validateForm()) return;

    const y = parseFloat(yInput.value.trim().replace(',', '.'));
    // пасхалка
    if (y === 81) {
        const egg = document.getElementById('oscar-easter-egg');
        if (egg) {
            egg.classList.add('show');
            setTimeout(() => egg.classList.remove('show'), 1000);
        }
        yInput.value = '';
        validateForm();
        return;
    }

    const r = parseFloat(rHidden.value);

    // Дата, время и тд
    const dateString = new Date().toLocaleString("ru-RU", {
        timeZone: Intl.DateTimeFormat().resolvedOptions().timeZone,
        year: 'numeric',
        month: 'long',
        day: 'numeric',
        hour: '2-digit',
        minute: '2-digit',
        second: '2-digit'
    });

    checkboxes.forEach(cb => {
        if (cb.checked) {
            const x = parseFloat(cb.value);
            const hit = checkHit(x, y, r);

            history.push({
                x: x,
                y: y,
                r: r,
                hit: hit,
                time: dateString
            });
        }
    });

    localStorage.setItem(STORAGE_KEY, JSON.stringify(history));

    renderHistory();
    drawGraph();
});

function renderHistory() {
    resultsBody.innerHTML = '';
    [...history].reverse().forEach(rec => {
        const tr = document.createElement('tr');
        tr.innerHTML = `
            <td>${rec.x}</td>
            <td>${rec.y}</td>
            <td>${rec.r}</td>
            <td style="color: ${rec.hit ? 'green' : 'red'}; font-weight: bold;">
                ${rec.hit ? 'Попадание' : 'Промах'}
            </td>
            <td>${rec.time}</td>
        `;
        resultsBody.appendChild(tr);
    });
}

function drawGraph() {
    ctx.clearRect(0, 0, width, height);
    ctx.fillStyle = '#3399FF';

    // Прямоугольник
    ctx.fillRect(center - R_PIXELS, center - R_PIXELS / 2, R_PIXELS, R_PIXELS / 2);

    // Четверть круга
    ctx.beginPath();
    ctx.moveTo(center, center);
    ctx.arc(center, center, R_PIXELS, -Math.PI / 2, 0, false);
    ctx.closePath();
    ctx.fill();

    // Треугольник
    ctx.beginPath();
    ctx.moveTo(center, center);
    ctx.lineTo(center + R_PIXELS, center);
    ctx.lineTo(center, center + R_PIXELS / 2);
    ctx.closePath();
    ctx.fill();

    // Оси
    ctx.strokeStyle = '#000';
    ctx.lineWidth = 1;
    ctx.beginPath();

    // Ось X
    ctx.moveTo(0, center);
    ctx.lineTo(width, center);
    ctx.lineTo(width - 5, center - 5);
    ctx.moveTo(width, center);
    ctx.lineTo(width - 5, center + 5);

    // Ось Y
    ctx.moveTo(center, height);
    ctx.lineTo(center, 0);
    ctx.lineTo(center - 5, 5);
    ctx.moveTo(center, 0);
    ctx.lineTo(center + 5, 5);

    ctx.stroke();

    // Обозначения
    ctx.fillStyle = '#000';
    ctx.font = '12px Arial';

    // Ось X
    ctx.fillText('R', center + R_PIXELS - 5, center + 15);
    ctx.fillText('R/2', center + R_PIXELS / 2 - 10, center + 15);
    ctx.fillText('-R', center - R_PIXELS - 5, center + 15);
    ctx.fillText('-R/2', center - R_PIXELS / 2 - 10, center + 15);
    ctx.fillText('x', width - 10, center - 10);

    // Ось Y
    ctx.fillText('R', center + 10, center - R_PIXELS + 4);
    ctx.fillText('R/2', center + 10, center - R_PIXELS / 2 + 4);
    ctx.fillText('-R', center + 10, center + R_PIXELS + 4);
    ctx.fillText('-R/2', center + 10, center + R_PIXELS / 2 + 4);
    ctx.fillText('y', center + 10, 10);

    // Засечки
    ctx.beginPath();
    [R_PIXELS, R_PIXELS/2, -R_PIXELS, -R_PIXELS/2].forEach(p => {
        // по X
        ctx.moveTo(center + p, center - 3);
        ctx.lineTo(center + p, center + 3);
        // по Y
        ctx.moveTo(center - 3, center + p);
        ctx.lineTo(center + 3, center + p);
    });
    ctx.stroke();

    if (currentR && currentR > 0) {
        history.forEach(rec => {
            let drawX = center + (rec.x / currentR) * R_PIXELS;
            let drawY = center - (rec.y / currentR) * R_PIXELS;

            ctx.beginPath();
            ctx.arc(drawX, drawY, 4, 0, 2 * Math.PI, false);
            ctx.fillStyle = rec.hit ? '#4CAF50' : '#F44336';
            ctx.fill();
            ctx.strokeStyle = '#222';
            ctx.stroke();
        });
    }
}



================================================
FILE: tasks.md
================================================
1. поле ввода функции (кастомизация области попадания) модуль, тригонометрия, степень
2. изменение отрисовки и точек попадания относительно r 
3. div убрать, дотабличить вёрстку
4. На пустые значение не ругаться  
5. отчёт



================================================
FILE: docs/requirements.md
================================================
Частые ошибки:

1. Использование alert для вывода сообщений об ошибках.
2. Отсутствие человекочитаемых сообщений об ошибках при вводе некорректных значений. Например, вывод стандартного сообщения об ошибке от JSF валидатора не является человекочитаемым сообщением об ошибке.
3. Отсутствие валидации значений на серверной стороне.
4. Некорректная обработка числовых значений с большой точностью. Ограничение числа знаков после запятой - не решение!
5. Отсутствие корректной обработки чисел с разделителем запятая.
6. Отсутствие/несоответсвие необходимых пунктов из задания к лабораторной.
7. "Использование микроскопа для забивания гвоздей" т.е. использование каких-либо технологий без особой необходимости, переусложнение исходного кода.
8. Ипользование библиотек компонентов в несоотвествии с вариантом. Если в варианте у вас написано использовать компоненты React Toolbox/Prime React/что-то_другое, то вы обязаны использовать их, а не то, что Вам больше понравилось.
9. Несоответствие компонентов ввода X, Y, R тому, что написано в варианте.
10. Отстуствие отправки точки и добавления ее в таблицу при нажатии на график (начиная со второй лабораторной работы).
11. Ограничение возможных координат точки при клике по графику (например, если x: Button [-2, -1,5, -1, -0,5, 0], то с графика можно отправить точку с координатой x=-0.345).
12. Отсутствие корректной обработки отрицательного радиуса. Т.е. если в варианте есть отрицательный радиус, необходимо это обрабатывать как корректный случай — например, перерисовывать фигуру симметрично относительно начала координат.
13. Отсутствие перерисовки графика при изменении выбранного радиуса.
14. Изменение логики работы компонентов ввода. Например, если компонент подразумевает возможность множественного выбора, то при выборе нескольких элементов необходимо отправлять на сервер несколько точек; Если такой компонент задан в качестве радиуса, то при множетсвенном выборе радиусов необходимо отображать несоклько графиков.
15. Некорректная работа с пользователями:
15.1. При попытке зайти с разных браузеров в одного и того же пользователя есть два варианта: либо автоматическое обновление точек во втором окне при добавлении их с первого без необходимости обновлять старницу, либо запрет заходить с разных мест одному пользователю, т.е. при попытке логина уже залогиненного пользователя с другого окна/браузера разлогинивать его в первом.
15.2. При возможности залогиниться в разных пользователей с разных вкладок одного окна браузера недопустим кейс, когда при обновлении страницы пользователь внезапно меняется с одного на другого.
15.3. При невозможности залогиниться в разных пользователей с разных вкладок одного окна браузера необходимо учесть следующее:
15.3.1. Если во вкладке_1 пользователь залогинен, то при открытии вкладки_2 мы попадаем в аккаунт того же пользователя без необходимости выполнять авторизацию дополнительно.
15.3.2. Если в вкладке_1 пользователь вышел из аккаунта, то во вкладке_2 необходимо либо разлогинить сразу, либо при совершении какого-то действия выводить сообщение о том, что был совершен выход из аккаунта/вы не авторизованы/что-то_в_этом_духе и производить редирект на страницу логина.



================================================
FILE: docs/task.md
================================================
# Задача

![картинка задания](task.png)


Разработать HTML-страницу с JS и CSS, определяющую попадание точки на координатной плоскости в заданную область. Область задается по варианту и приведена выше на рисунке. Требуется нарисовать ее средствами Canvas.

Кроме координатной плоскости, на странице должна быть HTML форма с полями X, Y, R. На рисунке по вашему варианту кроме самой координатной области определены типы полей формы и область допустимых значений для каждого поля. Страница должна содержать сценарий на языке JavaScript, осуществляющий валидацию значений, вводимых пользователем в поля формы. Любые некорректные значения (например, буквы в координатах точки или отрицательный радиус) должны блокироваться.

Точки должны определяться на основе данных формы, факт попадания точки должен вычисляться при помощи JS в момент отправки формы. Результаты проверок должны отображаться в таблице на странице, а также сохраняться при перезагрузке страницы. Для реализации сохранения точек между перезагрузками требуется использовать LocalStorage.

Помимо данных из формы в таблице результатов должно отображаться дата и время, когда была выполнена проверка. Дата и время должны отображться с учетом часового пояса клиентского устройства, т.е. при смене часового пояса на устройстве отображаемые даты и время должны корректным образом пересчитаться, чтобы отображать тот же самый момент времени. Требуется отображать дату и время строго в русской локализации.

### Разработанная HTML-страница должна удовлетворять следующим требованиям:

1. Для расположения текстовых и графических элементов необходимо использовать табличную верстку.
2. Таблицы стилей должны располагаться в самом веб-документе.
3. При работе с CSS должно быть продемонстрировано использование селекторов дочерних элементов, селекторов классов, селекторов идентификаторов, селекторов элементов, а также такие свойства стилей CSS, как наследование и каскадирование.
4. HTML-страница должна иметь «шапку», содержащую ФИО студента, номер группы и номер варианта. При оформлении шапки необходимо явным образом задать шрифт (monospace), его цвет и размер в каскадной таблице стилей.
5. Отступы элементов ввода должны задаваться в пикселях.