<img id="img1" src=""/>
<script>
function fileChange(obj) {
var url = obj.value url = "file:///" + url.replace("\\",'/');
alert(url);
document.getElementById("img1").src= url;
}
</script>
<input type="file" onchange="fileChange(this);" />
关键是:url = "file:///" + url.replace("\\",'/')