<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<meta name="viewport" content="maximum-scale=1.0,minimum-scale=1.0,user-scalable=0,width=device-width,initial-scale=1.0" />
<script>
function init() {
var canvas = document.createElement(‘canvas‘)
var ctx = canvas.getContext(‘2d‘);
var img = new Image();
img.src = "临时图片/1.png";
img.onload = function() {
//原图的大小
ctx.drawImage(img, 0, 0, 100, 100);
console.log(canvas.toDataURL())
document.getElementById(‘imgbase64‘).src = canvas.toDataURL();
}
}
</script>
</head>
<body onload="init()">
<img id="imgbase64" src="" />
</body>
</html>
原文：http://www.cnblogs.com/zhaojia-dream/p/5570761.html