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<title>无标题文档</title>
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body{
background:pink;
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background:white;
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window.onload = function ()
{
var oC = document.getElementById('c1'); var oGC = oC.getContext('2d'); oC.onmousedown = function (ev)
{
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oGC.moveTo(ev.clientX - oC.offsetLeft, ev.clientY - oC.offsetTop); document.onmousemove = function (ev)
{
var ev = ev || event;
oGC.lineTo(ev.clientX - oC.offsetLeft, ev.clientY - oC.offsetTop);
oGC.stroke();
}
document.onmouseup = function ()
{
document.onmousemove = null;
document.onmouseup = null;
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<span>请升级您的浏览器</span>
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