js 上传图片预览

<head>
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
</head> 
<body>
<div id="localImag">
    <img id="preview" style="display:block; border:1px solid red; width: 150px; height: 180px;">
</div>
<input id="doc" type="file" name="file" onchange="javascript:setImagePreview();">
<script type="text/javascript">
    //下面用于图片上传预览功能
    function setImagePreview(avalue) {
        var docObj=document.getElementById("doc"); 
        var imgObjPreview=document.getElementById("preview");
        if(docObj.files && docObj.files[0]){
            imgObjPreview.src = window.URL.createObjectURL(docObj.files[0]);
        }else{    
            //IE低版本下,使用滤镜
            docObj.select();
            var imgSrc = document.selection.createRange().text;
            var localImagId = document.getElementById("localImag");
            //必须设置初始大小
            localImagId.style.width = "150px";
            localImagId.style.height = "180px";
            //图片异常的捕捉,防止用户修改后缀来伪造图片
            try{
                localImagId.style.filter="progid:DXImageTransform.Microsoft.AlphaImageLoader(sizingMethod=scale)";
                localImagId.filters.item("DXImageTransform.Microsoft.AlphaImageLoader").src = imgSrc;
            }catch(e){
                alert("您上传的图片格式不正确,请重新选择!");
                return false;
            }
            imgObjPreview.style.display = 'none';
            document.selection.empty();
        }
    } 
</script>
</body>

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转载自www.cnblogs.com/justSmile2/p/10034055.html