How to get the value that return from the javascript function?

Question

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How to return the value of a function after the result of an ajax call has come?

I have one function that use to count the quantity of item in my controller.

function GetQtyItem() {
  var qty;
  var urlQuantity = "Quotation/CountQuantity";
  $.getJSON(urlQuantity, function (quantity) {
      qty = quantity.ja;
  });
  alert(qty); //3
  return qty;
}

I included the file name with the correct part, and called this function in another view of my asp.net mvc project :

<script language="javascript" type="text/javascript">
  var i = GetQtyItem();
  alert(i);
</script>

But the result in the alert dialog is Undefined.

Could any one tell me, how can I alert it with the correct value(3). Thanks in advanced.

So you got two alerts, the first with 3 and the second undefined? — Satya, Sep 28 '12 at 04:09
No, Satya. The first alert is undefined, and the second alert is 3. — Nothing, Sep 28 '12 at 04:11
That's the problem. Your function is defined after it is called. Put the function definition before the call. — Satya, Sep 28 '12 at 04:11

Ryan Wheale · Accepted Answer · 2012-09-28T04:17:01.880

1

$.getJSON is an AJAX request... which takes time. You must wait for the data to come back, and then alert the result.

Try this:

var qty, i;
function GetQtyItem() {
  var urlQuantity = "Quotation/CountQuantity";
  return $.getJSON(urlQuantity, function (quantity) {
      qty = quantity.ja;
      alert('Request is done');
  });
}

i = GetQtyItem();
i.done(function() {
  alert("Quantity is " + qty);
});

edited Sep 28 '12 at 04:17

answered Sep 28 '12 at 04:09

Ryan Wheale

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How to get the value that return from the javascript function?

1 Answers1