html5 图片上传 预览

<script>

    if (typeof FileReader == 'undefined') {
        alert("抱歉，你的浏览器不支持FileReader");
    }

function doChange(obj)
{
    html5ImgLocalReader('uploadpic1', 'img1');
}

function html5ImgLocalReader(fileId, imgId) {
    var file1 = document.getElementById(fileId);
    var file = file1.files[0];    
    var reader = new FileReader();
    reader.readAsDataURL(file);

    reader.onload = function (e) {
        document.getElementById(imgId).src=this.result;
        //document.getElementById(imgId).style.backgroundImage = "url("+this.result+")";
    }
}
</script>