javscript上传图片前预览的方法setPreViewImage()

时间：2022-10-08 10:22:08
<!doctype html>

<html lang="en">

 <head>

 <meta charset="UTF-8">

 <meta name="Generator" content="EditPlus?">

 <meta name="Author" content="">

 <meta name="Keywords" content="">

 <meta name="Description" content="">

 <title>Document</title>

 </head>

 <body>

 <script>

function setImagePreview() {

    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 = '120px';

    /*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 = "120px";

    /*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>

<input type=file name="doc" id="doc" onchange="javascript:setImagePreview();">

<p>

<div id="localImag">

<img id="preview" width=-1 height=-1 style="diplay: none" />

</div>

</p>

 </body>

</html>

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