js实现图片上传并即时显示

<label for="thumbnail" class="col-md-3 control-label">缩略图</label>
<div class="col-md-6">
<input type="file" class="form-control" id="thumbnail" name="thumbnail">
</div>

<script>
function getObjectURL(file) {
var url = null ;
if (window.createObjectURL!=undefined) { // basic
url = window.createObjectURL(file) ;
} else if (window.URL!=undefined) { // mozilla(firefox)
url = window.URL.createObjectURL(file) ;
} else if (window.webkitURL!=undefined) { // webkit or chrome
url = window.webkitURL.createObjectURL(file) ;
}
return url ;
}

$('#thumbnail').change(function() {
var eImg = $('<img />');
eImg.attr('src', getObjectURL($(this)[0].files[0])); // 或 this.files[0] this->input
$(this).after(eImg);});
</script>