jQuery加减

var num1 = 123;

var num2=123;

var sum = num1+num2;

结果是246;

<input type="text" id="txt1" value="123" />

<input type="text" id="txt2" value="123" />

var num1= $("#txt1").val();

var num2 = $("#txt2").val();

var sum= num1+num2;

结果是123123;

var sum= num1*1+num2*1;

结果是246;