Upload image preview JS script Input file image preview implementation example-JS Tutorial-php.cn

Upload image preview JS script Input file image preview implementation example

高洛峰

Release： 2016-12-24 17:28:27

Original

1177 people have browsed it

When working on a project in Shenzhen, we need a function for users to upload avatar previews! I have searched a lot online, but are not very satisfied. Either it is flash, or it returns the image path after Ajax upload, or it is simply unusable. Fortunately, someone had written a picture preview function before this project, and I dug it out. I made a record here for my own convenience in the future, and for the convenience of other friends who need it!

The code is very simple, as follows:

<!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 = &#39;block&#39;;
imgObjPreview.style.width = &#39;150px&#39;;
imgObjPreview.style.height = &#39;180px&#39;; 
//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 = &#39;none&#39;;
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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The test can be used in IE8, FF12.0 and Google chrome 28.0.1500.72!

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