js上传图片预览

最近项目中用到的图片上传前预览功能,兼容IE6-9,FF
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<body>
<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>
<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
= '300px';
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 = "300px";
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>
</body>
</html>

 


由于项目中有多个上传按钮,需要针对网上示例作一些修改,实际使用代码:

View Code
function setImagePreview(fileObj, previewObj, localImg) {
var docObj=document.getElementById(fileObj);
var imgObjPreview=document.getElementById(previewObj);
if(docObj.files && docObj.files[0]){
//火狐下,直接设img属性
imgObjPreview.style.display = 'block';
imgObjPreview.style.width = '120px';
imgObjPreview.style.height = '80px';
//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(localImg);
//必须设置初始大小
localImagId.style.width = "120px";
localImagId.style.height = "80px";
//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;
}




posted @ 2012-03-06 12:23  上善若水.  阅读(17709)  评论(13编辑  收藏  举报