<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>h5上传图片</title>
</head>
<body>
<input type="file" name="file" onchange="showPreview(this)" />
<img id="portrait" src="" width="70" height="75">
<script>
// 先判断浏览器对FileReader的支持
/*if(window.FileReader) {
var fr = new FileReader();
// add your code here
}
else {
alert("Not supported by your browser!");
}*/
function showPreview(source) {
var file = source.files[0];
if(window.FileReader) {
var fr = new FileReader();
fr.onloadend = function(e) {
document.getElementById("portrait").src = e.target.result;
};
fr.readAsDataURL(file);
}
}
</script>
</body>
</html>
原文：http://www.cnblogs.com/studyh5/p/8011924.html