js上传图片并预览

时间：2020-11-30 16:49:37
<!DOCTYPE html>
<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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