//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：