下面我使用这个脚本来设置一个文本框值..
$('#sub').click(function(){
var num1 = $('#text1').val();
var num2 = $('#text2').val();
var newVal = (num1+2)*(num2/4);
var nextVal =(num1+4)*(num2/2);
$(#text1).val(newVal); //setting the textbox value here