Enter only numbers and minus sign in textbox

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Hi,

I am using this code to enter only numbers in a textbox and works perfectly.

<script type="text/javascript">
        function fnAllowNumeric() {
            if ((event.keyCode < 48 || event.keyCode > 57) && event.keyCode != 8) {
                event.keyCode = 0;
                alert("Please Enter Number Only");
                return false;
            }
        }
</script>

Now on top of this I should allow minus sign to be entered at the start. Can anyone suggest me some solutions?

Posted 1-Jun-15 1:07am

vignesht50

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2 solutions

Solution 1

Try JavaScript isNaN() Function[^]
+++++[round 2]+++++
An example to adapt:

XML

<script>
function myFunction() {
    var a = document.getElementById("txt").value.trim();
    if (isNaN(a) || a == ""){
        alert("Not a valid number!");
    } else {
        alert("A valid number!");
    }
}
</script>

<input type="text" value="" id="txt">
<button onclick="myFunction()">Click me</button>

Posted 1-Jun-15 1:18am

Peter Leow

Updated 1-Jun-15 2:04am

v2

Comments

vignesht50 1-Jun-15 7:41am

I can validate for numbers alone, but I need to allow to input ' - ' sign too.

Peter Leow 1-Jun-15 8:05am

See the added example code and adapt.

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RajeeshMenoth · Accepted Answer · 2015-06-01T02:25:00

Solution 2

Hi,

Ref This Demo : Enter only numbers and minus sign in textbox

Posted 1-Jun-15 2:25am

RajeeshMenoth