如何计算两个输入表单字段并将值放入另一个而不使用jquery提交表单？

Question

I know this is an extremely basic question but I'm stuck on this. I have two input boxes and I want to calculate those inputs and show the result into another input (3rd one) immediately without the need of a submit button. I means, once I start entering the values into the input and the result will shows live in the 3rd input which is the represent the result...

<input type="text" class="input value1">
<input type="text" class="input value2">
<input type="text" disabled="disabled" id="result">

<script>
 $(document).ready(function(){
      var val1 = $(".value1").val();
      var val2 = $(".value2").val();
      $(".input").keyup(function(){
         $("#result").text(val1+val2);
       });
});
</script>

Answer 1

Put val1 and val2 in keyup statement.

$(document).ready(function(){
    $(".input").keyup(function(){
          var val1 = +$(".value1").val();
          var val2 = +$(".value2").val();
          $("#result").val(val1+val2);
    });
});

Look at fiddle: http://jsfiddle.net/g7zz6/

Answer 2

Under the assumption of SUM as you stated, the inputs will be numberic in nature.

$(".input").on("change", function(){
    var ret = Number($(".value1").val()) + Number($(".value2").val());
    $("#result").val(ret);
}

Answer 3

just set the text value, also you need to parse them as other wise they will be concatenated as strings.

$(document).ready(function () {
    var val = parseInt($(".value1").val()) + parseInt($(".value2").val());
    $("#result").text(val);
});

Live Demo

Answer 4

 function addinput(){ 
   var x= Number(document.getElementById("first").value);
   var y= Number(document.getElementById("second").value);
   var z= Number(x+y);
   document.getElementById("l").value = Number(z);     
 }