html input type=file 選擇圖片,圖片預覽 純html js實現圖片預覽

weixin_33958585發表於2018-05-02
HTMLJS
<!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">
        //下面用於圖片上傳預覽功能
        function setImagePreview(avalue) {
            var docObj = document.getElementById("doc");

            var imgObjPreview = document.getElementById("preview");
            if (docObj.files && docObj.files[0]) {
                //火狐下，直接設img屬性
                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()方式獲取，需要一下方式
                imgObjPreview.src = window.URL.createObjectURL(docObj.files[0]);
            } else {
                //IE下，使用濾鏡
                docObj.select();
                var imgSrc = document.selection.createRange().text;
                var localImagId = document.getElementById("localImag");
                //必須設定初始大小
                localImagId.style.width = "150px";
                localImagId.style.height = "180px";
                //圖片異常的捕捉，防止使用者修改字尾來偽造圖片
                try {
                    localImagId.style.filter = "progid:DXImageTransform.Microsoft.AlphaImageLoader(sizingMethod=scale)";
                    localImagId.filters.item("DXImageTransform.Microsoft.AlphaImageLoader").src = imgSrc;
                } catch (e) {
                    alert("您上傳的圖片格式不正確，請重新選擇!");
                    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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