input file图片上传预览js实现

//头像上传预览
    $("#up").change(function() {
        var $file = $(this);
        var fileObj = $file[0];
        var windowURL = window.URL || window.webkitURL;
        var dataURL;
        var $img = $("#ImgPr");
        if(fileObj && fileObj.files && fileObj.files[0]){
        dataURL = windowURL.createObjectURL(fileObj.files[0]);
        $img.attr(‘src‘,dataURL);
        }else{
        dataURL = $file.val();
        var imgObj = document.getElementById("ImgPr");
        imgObj.style.filter = "progid:DXImageTransform.Microsoft.AlphaImageLoader(sizingMethod=scale)";
        imgObj.filters.item("DXImageTransform.Microsoft.AlphaImageLoader").src = dataURL;
         
        }
    });

<div class="picbtn"><img id="ImgPr" src="images/neik.png"</div>
<a class="chooseimg" href="#"><input type="file" id="up">从手机相册中选择</a>