js判断文件格式及大小

//判断照片大小
function getPhotoSize(obj){
	photoExt=obj.value.substr(obj.value.lastIndexOf(".")).toLowerCase();//获得文件后缀名
	if(photoExt!='.jpg'){
		alert("请上传后缀名为jpg的照片!");
		return false;
	}
	var fileSize = 0;
    var isIE = /msie/i.test(navigator.userAgent) && !window.opera;            
	if (isIE && !obj.files) {          
   		 var filePath = obj.value;            
   		 var fileSystem = new ActiveXObject("Scripting.FileSystemObject");   
  		 var file = fileSystem.GetFile (filePath);               
   		 fileSize = file.Size;         
	}else {  
   		 fileSize = obj.files[0].size;     
 	} 
 	fileSize=Math.round(fileSize/1024*100)/100; //单位为KB
 	if(fileSize>=10){
 		alert("照片最大尺寸为10KB，请重新上传!");
 		return false;
 	}
}

jsp页面：

<input type="file" id="imgFile" name="upload" style="width:150px;" onchange="getPhotoSize(this)"/>