图片上传并显示（兼容ie），图片大小判断

一、上传并显示

HTML
<div id="swf" style="margin: 0 auto;text-align: center;">
    <img src="/assets/img/default.jpg" height="180px" width="180px"
         id="logoshow">
</div>
<div id="headview" style="text-align: center;margin: 0 auto;">
    <input type="file" id="logo" name="logo" style=" 180px;"
           onchange="previewImage(this)">
</div>

JS
function previewImage(file){
    var div = document.getElementById('swf');
    if (file.files && file.files[0]) {//HTML5
        var img = document.getElementById('logoshow');
        var reader = new FileReader();
        reader.readAsDataURL(file.files[0]);
        reader.onload = function (evt) {
            img.src = evt.target.result;
            img.style.width= "180px";
        };
    }
    else //兼容IE，滤镜
    {
        alert("filter");
        var sFilter = 'filter:progid:DXImageTransform.Microsoft.AlphaImageLoader(sizingMethod=scale,src="';
        file.select();
        file.blur();
        var src = document.selection.createRange().text;
        var img = document.getElementById('logoshow');
        img.filters.item('DXImageTransform.Microsoft.AlphaImageLoader').src = src;
        div.innerHTML = "<img id=logoshow style='margin:0px auto;180px;height:180px;" + sFilter + src + "\"'>";
    }
}

　　

二、判断大小，IE10才有file功能

JS判断文件大小
<input id="file" type="file" onchange="filefujianChange(document.getElementById('file'))">

<script type="text/javascript">
	function filefujianChange(target) {
		var fileSize = 0;         
		if (!target.files) {     
			var filePath = target.value;     
			var fileSystem = new ActiveXObject("Scripting.FileSystemObject");        
			var file = fileSystem.GetFile (filePath);     
			fileSize = file.Size;    
		} else {    
			fileSize = target.files[0].size;     
		}   
		var size = fileSize / 1024;
		alert(size);    
		if(size>2000){  
			alert("附件不能大于2M");
			target.value="";
			return
		}
		var name=target.value;
		var fileName = name.substring(name.lastIndexOf(".")+1).toLowerCase();
		alert(fileName);
		if(fileName !="jpg" && fileName !="jpeg" && fileName !="pdf" && fileName !="png" && fileName !="dwg" && fileName !="gif" ){
			alert("请选择图片格式文件上传(jpg,png,gif,dwg,pdf,gif等)！");
			target.value="";
			return ;
		}
	}
</script>