jQuery adding 2 numbers from input fields

13

I am trying to add two values of alert boxes but I keep getting a blank alert box. I don't know why.

$(document).ready(function(){
    var a = $("#a").val();
    var b = $("#b").val();   
    $("submit").on("click", function(){
        var sum = a + b;
        alert(sum);         
    })
})

This question is tagged with javascript jquery

~ Asked on 2013-04-29 00:00:30

The Best Answer is


45

Adding strings concatenates them:

> "1" + "1"
"11"

You have to parse them into numbers first:

/* parseFloat is used here. 
 * Because of it's not known that 
 * whether the number has fractional places.
 */

var a = parseFloat($('#a').val()),
    b = parseFloat($('#b').val());

Also, you have to get the values from inside of the click handler:

$("submit").on("click", function() {
   var a = parseInt($('#a').val(), 10),
       b = parseInt($('#b').val(), 10);
});

Otherwise, you're using the values of the textboxes from when the page loads.

~ Answered on 2013-04-29 00:02:11


7

<script type="text/javascript">
    $(document).ready(function () {
        $('#btnadd').on('click', function () {
            var n1 = parseInt($('#txtn1').val());
            var n2 = parseInt($('#txtn2').val());
            var r = n1 + n2;
            alert("sum of 2 No= " + r);
            return false;
        });
        $('#btnclear').on('click', function () {
            $('#txtn1').val('');
            $('#txtn2').val('');
            $('#txtn1').focus();
            return false;
        });
    });
</script>

~ Answered on 2013-12-13 07:19:31


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