上传图片带预览功能兼容IE和火狐等主流浏览器

 <!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>图片上传</title>
<script src="test.js" language="javascript"></script>
</head>
<body>
     <input type="file" name="doc" id="doc" onchange="setImagePreview('doc','preview','localImag');"/>
     <div id="localImag"><img id="preview" width=-1 height=-1 style="diplay:none" /></div>
</body>
</html>
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;
}
原文地址:https://www.cnblogs.com/mvv118/p/3911736.html