Jquery文本框赋值

< script src = " http://ajax.googleapis.com/ajax/libs/jquery/1.4.2/jquery.min.js "  type = " text/javascript " ></ script >
     < script type = " text/javascript " >
    jQuery(function(){
         $( " #txt1 " ).blur( function () { 
            $( " #txt2 " ).val( "" );
            $( " #txt3 " ).val( "" );
             if ($( this ).val() <= 10 && $( this ).val() > 0 ){
                $( " #txt2 " ).val( " 一级 " );
                $( " #txt3 " ).val( " 优 " );
            }
         }); 
    });
</ script >