Onblur firing before it is called.

--scenario

<pre>A textbox is there. I am allowing user to enter only single dot.

Like 34.56

if 34. (then it will become 34)[which i am taking care of it in onblur]


--Now suppose the user enters a number like 342.53. 
then message will appear "alert("Please enter numeric value!");"
--then i was making the text of textbox to be empty

--But suppose user enterd a big number like  34245.454.
then message will appear "alert("Please enter numeric value!");"
--then the textbox will be empty
--and the user has to retype again the number.

So text which i was making empty i removed that line.
So now user click a number  3465.45.
then message will appear "alert("Please enter numeric value!");"
So now user click a number  3465.45..
then message will appear "alert("Please enter numeric value!");"

But when i click outside the textbox then the number now is 3465.45..

So what i thought like in onblur function

i will check if it is a valid number or not. If it is not a valid number then I will make the text to be empty

<script type="text/javascript">
        function validate1() {
            var num = document.getElementById("txtid").value;
            if (isNaN(num) == true) {
                alert("Please enter numeric value!");
                return false;
            }
            else
                return true;
        }

   </script>
  <script type="text/javascript">
      function onblurvalidate() {
          var num = document.getElementById("txtid").value;
          if (isNaN(num) == true) {
              document.getElementById("txtid").value = "";
              return false;
          }

            var length = num.length;
            var num1 = num + '';
            var dotindex = num1.indexOf(".");
            if (length == (dotindex+1))
            {
                document.getElementById("txtid").value = num.substring(0, num.length - 1);
            }

      }
    </script>

But to my amazement i got the result like when i entered a wrong number suppose

34.45.
the message appeared "alert("Please enter numeric value!");"
And the text is empty.

How this is possible. As I have not clicked outside the textbox,So it should not fire. Kindly help me understanding this.