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Upload image preview JS script Input file image preview implementation example

高洛峰

Dec 24, 2016 pm 05:28 PM

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  src="/static/imghwm/default1.png"  data-src="http://blog.chuangling.net/Public/images/top.jpg"  class="lazy"  id="preview"     style="max-width:90%"  style="max-width:90%" style="display: block; width: 150px; height: 180px;" alt="Upload image preview JS script Input file image preview implementation example" ></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>

The test can be used in IE8, FF12.0 and Google chrome 28.0.1500.72!

For more upload image preview JS script Input file image preview implementation examples, please pay attention to PHP Chinese for related articles net!

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