jquery校验输入框是否有值以及控制其长度

$(document).ready(function(){
if($("#messageBox").length>0){
$("#messageBox").hide();
}
$.validator.setDefaults({      
submitHandler: function(form) {  
     form.submit();   
    }      
}); 
$("#editFavo").validate({ //editFavo为From的id errorLabelContainer: "#messageBox",  //messageBox为一个div域 例：<div id="messageBox"></div>
debug:true,
wrapper: "li",
rules:{
"webUrl":{required:true}, //webUrl为文本框的id(被校验的id)下面属性与此一样
"title":{required:true,byteRangeLength2:[1,48]},
"descript":{required:true,byteRangeLength2:[1,280]}
},
messages:{
"webUrl":{required:'<s:text name="categoryName.yes"/>'},//与上面依依对应的消息提示语(链接不能为空)
"title":{required:'<s:text name="categoryName.yes"/>'},
"descript":{required:'<s:text name="categoryName.yes"/>'}
}
});
$.validator.addMethod("byteRangeLength2", function(value, element, param) {     //校验输入字符的长度
  var length = value.length;    
  for(var i = 0; i < value.length; i++){    
   if(value.charCodeAt(i) > 127){    
    length++;    
   }    
  }    
  return this.optional(element) || ( length >= param[0] && length <= param[1] );    
},"<s:text name='categoryName.length'/>");
})