按钮单击我只想将元素放在画布上,但它不起作用。这是我写的代码:Java脚本html5画布
<script language="javascript" type="text/javascript">
function image()
{
var c=document.getElementById("myCanvas");
var ctx=c.getContext("2d");
ctx.clear();
ctx.setTransform(-1, 0, 0, 1, 200, 200);
context.clear(true)
var imgobj=new Image();
imgobj.onload=function()
{
ctx.drawImage(imgobj,69,50);
}
imgobj.src='images.jpg';
}
function circle()
{
var c=document.getElementById("myCanvas");
var ctx=c.getContext("2d");
ctx.clear();
// do some more drawing
ctx.setTransform(-1, 0, 0, 1, 200, 200);
// do some drawing with the new transform
context.clear(true);
ctx.beginPath();
ctx.arc(95,50,40,0,2*Math.PI);
ctx.stroke();
}
function line()
{
var c=document.getElementById("myCanvas");
var ctx=c.getContext("2d");
ctx.clear();
// do some more drawing
ctx.setTransform(-1, 0, 0, 1, 200, 200);
// do some drawing with the new transform
context.clear(true);
ctx.moveTo(0,0);
ctx.lineTo(200,100);
ctx.stroke();
</script>
</head>
<body>
<h1>Demo of HTM5</h1>
<div class="canvas1" align="left">
<canvas id="myCanvas" width="300" height="300" style="border:1px solid #000000;">
</canvas>
<p><button onclick="circle()"> Draw Circle</button></p>
<p><button onclick="line()"> Draw Line</button></p>
<p><button onclick="image()"> Display Image</button></p>
</div>
</body>
</html>
检查您的'onclick ='行的语法。你正在寻找更像这样的东西:'onclick = function(){circle(); }'。 –
我做到了这一点,还bt仍然不工作... – jShubh