input上传文件显示图片缩略图

时间：2021-10-05 21:10:59
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
    <title>By：DragonDean</title>
    <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])
            {
//火狐下，直接设img属性
                imgObjPreview.style.display = 'block';
                imgObjPreview.style.width = '150px';
                imgObjPreview.style.height = '180px';
//imgObjPreview.src = docObj.files[0].getAsDataURL();

//火狐7以上版本不能用上面的getAsDataURL()方式获取，需要一下方式
                imgObjPreview.src = window.URL.createObjectURL(docObj.files[0]);
            }
            else
            {
//IE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();
            }
            return true;
        }

    </script>
</head>

<body>
<table width="100%" border="0" cellspacing="0" cellpadding="0">
    <tbody>
    <tr>
        <td height="101" align="center">
            <div id="localImag"><img id="preview" src="http://blog.chuangling.net/Public/images/top.jpg" width="150" height="180" style="display: block; width: 150px; height: 180px;"></div>
        </td>
    </tr>
    <tr>
        <td align="center" style="padding-top:10px;"><input type="file" name="file" id="doc" style="width:150px;" onchange="javascript:setImagePreview();"></td>
    </tr>
    </tbody>
</table>
</body>
</html>

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