<canvas id="myCanvas" width="300" height="150" style="border:1px solid #d3d3d3;">

您的浏览器不支持 HTML5 canvas 标签。

</canvas>

<script>

var c=document.getElementById("myCanvas");

var ctx=c.getContext("2d");

ctx.beginPath();

ctx.moveTo(20,20);

ctx.lineTo(20,100);

ctx.lineTo(70,100);

ctx.stroke();

</script>

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