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<head>
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window.onload = function() {
    var ctx = document.getElementById("c1").getContext("2d");

    ctx.lineWidth = 5;

    ctx.setLineDash([ 5, 10 ]);  // 5 on, 10 off
    ctx.moveTo(50, 50);
    ctx.lineTo(250, 50);
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    ctx.moveTo(50, 100);
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    ctx.lineDashOffset = 5;
    ctx.setLineDash([ 5 ]);  // 5 on, 5 off
    ctx.moveTo(50, 150);
    ctx.lineTo(250, 150);
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    ctx.beginPath();

}
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</head>
<body style="padding: 0px; margin: 0px;">
  <div><canvas id="c1" width="300" height="300"></canvas></div>
</body>
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