Javascript Gantt Chart Open Source

<div class="container">
  <div class="header">
    <h1>Project Gantt Chart</h1>
    <p class="subtitle">Interactive timeline visualization</p>
  </div>

  <div class="legend">
    <div class="legend-item">
      <div class="legend-color" style="background: linear-gradient(135deg, #43e97b 0%, #38f9d7 100%);"></div>
      <span>Completed</span>
    </div>
    <div class="legend-item">
      <div class="legend-color" style="background: linear-gradient(135deg, #4facfe 0%, #00f2fe 100%);"></div>
      <span>In Progress</span>
    </div>
    <div class="legend-item">
      <div class="legend-color" style="background: linear-gradient(135deg, #fa709a 0%, #fee140 100%);"></div>
      <span>Pending</span>
    </div>
  </div>

  <div class="gantt-wrapper">
    <div class="gantt-container" id="ganttChart"></div>
  </div>
</div>

        * {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
        }

        body {
            font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
            background: linear-gradient(135deg, #4facfe 0%, #00f2fe 100%);
            padding: 20px;
            min-height: 100vh;
        }

        .container {
            max-width: 1400px;
            margin: 0 auto;
            background: white;
            border-radius: 16px;
            box-shadow: 0 20px 60px rgba(0, 0, 0, 0.15);
            overflow: hidden;
        }

        .header {
            background: linear-gradient(135deg, #4facfe 0%, #00f2fe 100%);
            color: white;
            padding: 30px;
            text-align: center;
        }

        h1 {
            font-size: 28px;
            margin-bottom: 8px;
        }

        .subtitle {
            font-size: 14px;
            opacity: 0.9;
        }

        .gantt-wrapper {
            padding: 30px;
            overflow-x: auto;
        }

        .gantt-container {
            min-width: 1000px;
        }

        .timeline-header {
            display: grid;
            grid-template-columns: 200px 1fr;
            margin-bottom: 2px;
            background: #f8f9fa;
            border-radius: 8px;
        }

        .task-header {
            padding: 15px;
            font-weight: 600;
            color: #333;
            border-right: 2px solid #e0e0e0;
        }

        .dates-header {
            display: flex;
            padding: 15px 0;
        }

        .date-column {
            flex: 1;
            text-align: center;
            font-size: 12px;
            color: #666;
            font-weight: 500;
        }

        .gantt-row {
            display: grid;
            grid-template-columns: 200px 1fr;
            margin-bottom: 10px;
            background: white;
            border: 1px solid #e0e0e0;
            border-radius: 8px;
            overflow: hidden;
            transition: transform 0.2s;
        }

        .gantt-row:hover {
            transform: translateX(4px);
            box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
        }

        .task-name {
            padding: 20px 15px;
            font-weight: 500;
            color: #333;
            border-right: 2px solid #e0e0e0;
            display: flex;
            flex-direction: column;
            justify-content: center;
        }

        .task-person {
            font-size: 12px;
            color: #888;
            margin-top: 4px;
        }

        .timeline {
            display: flex;
            position: relative;
            padding: 10px 0;
        }

        .timeline-cell {
            flex: 1;
            border-right: 1px solid #f0f0f0;
            position: relative;
        }

        .bar {
            position: absolute;
            height: 32px;
            top: 50%;
            transform: translateY(-50%);
            border-radius: 6px;
            display: flex;
            align-items: center;
            padding: 0 12px;
            color: white;
            font-size: 13px;
            font-weight: 500;
            cursor: pointer;
            transition: all 0.3s;
            box-shadow: 0 2px 8px rgba(0, 0, 0, 0.15);
        }

        .bar:hover {
            transform: translateY(-50%) scale(1.05);
            box-shadow: 0 4px 16px rgba(0, 0, 0, 0.25);
        }

        .bar.status-completed {
            background: linear-gradient(135deg, #43e97b 0%, #38f9d7 100%);
        }

        .bar.status-in-progress {
            background: linear-gradient(135deg, #4facfe 0%, #00f2fe 100%);
        }

        .bar.status-pending {
            background: linear-gradient(135deg, #fa709a 0%, #fee140 100%);
        }

        .legend {
            display: flex;
            justify-content: center;
            gap: 30px;
            padding: 20px;
            background: #f8f9fa;
            border-radius: 8px;
            margin: 20px 30px;
        }

        .legend-item {
            display: flex;
            align-items: center;
            gap: 8px;
            font-size: 14px;
        }

        .legend-color {
            width: 24px;
            height: 24px;
            border-radius: 4px;
        }

        .today-line {
            position: absolute;
            width: 2px;
            background: #ff4757;
            height: 100%;
            top: 0;
            z-index: 10;
        }

        .today-label {
            position: absolute;
            top: -25px;
            left: 50%;
            transform: translateX(-50%);
            background: #ff4757;
            color: white;
            padding: 4px 8px;
            border-radius: 4px;
            font-size: 11px;
            font-weight: 600;
            white-space: nowrap;
        }

    const tasks = [
            { name: 'Project Planning', person: 'John Doe', start: 1, duration: 3, status: 'completed' },
            { name: 'Design Phase', person: 'Jane Smith', start: 3, duration: 4, status: 'completed' },
            { name: 'Frontend Development', person: 'Mike Johnson', start: 5, duration: 6, status: 'in-progress' },
            { name: 'Backend Development', person: 'Sarah Williams', start: 6, duration: 5, status: 'in-progress' },
            { name: 'Database Setup', person: 'Tom Brown', start: 7, duration: 3, status: 'in-progress' },
            { name: 'API Integration', person: 'Emily Davis', start: 10, duration: 4, status: 'pending' },
            { name: 'Testing & QA', person: 'Chris Wilson', start: 12, duration: 3, status: 'pending' },
            { name: 'Deployment', person: 'Alex Martinez', start: 14, duration: 2, status: 'pending' }
        ];

        const totalDays = 16;
        const dates = [];
        const startDate = new Date('2025-01-01');

        for (let i = 0; i < totalDays; i++) {
            const date = new Date(startDate);
            date.setDate(date.getDate() + i);
            dates.push(date.toLocaleDateString('en-US', { month: 'short', day: 'numeric' }));
        }

        function renderGanttChart() {
            const container = document.getElementById('ganttChart');
            
            // Header
            let html = '<div class="timeline-header">';
            html += '<div class="task-header">Task / Assignee</div>';
            html += '<div class="dates-header">';
            dates.forEach(date => {
                html += `<div class="date-column">${date}</div>`;
            });
            html += '</div></div>';

            // Rows
            tasks.forEach(task => {
                const startPercent = (task.start / totalDays) * 100;
                const widthPercent = (task.duration / totalDays) * 100;

                html += '<div class="gantt-row">';
                html += `<div class="task-name">
                    <div>${task.name}</div>
                    <div class="task-person">${task.person}</div>
                </div>`;
                html += '<div class="timeline">';
                
                for (let i = 0; i < totalDays; i++) {
                    html += '<div class="timeline-cell"></div>';
                }

                html += `<div class="bar status-${task.status}" 
                    style="left: ${startPercent}%; width: ${widthPercent}%;"
                    title="${task.name}: ${task.duration} days">
                    ${task.duration}d
                </div>`;
                
                html += '</div></div>';
            });

            container.innerHTML = html;
        }

        renderGanttChart();