onChange for a textfield

Posted on 2006-07-21
Last Modified: 2011-10-03
Hi guys,

I want to know how I can make an alert, which will display the contents of a textfield, after the textfield's value has changed. I want this message to run only if:

- The contents of the field has changed from the original value.
- The field is no longer selected (eg, tab was pressed, or something else was clicked)

I only need this to work with Internet Explorer, any ideas guys?

Question by:Cyber-Drugs
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LVL 23

Accepted Solution

apresto earned 300 total points
ID: 17153664
Hi Cyber-Drugs,

var oldValue = "";

function alertOnChange( txtBox )
   if ( txtBox.value != oldValue )
       oldValue = txtBox.value;
       alert( oldValue );

onchange="alertOnChange( this );"

LVL 23

Expert Comment

ID: 17153702
sorry, stick it in the onBlur event
LVL 19

Assisted Solution

nschafer earned 200 total points
ID: 17153709
Hi Cyber-Drugs,

<script type="text/javascript">
var txtVal
function setVal() {
  txtVal = document.getElementById('YourTextBoxId').value

function checkVal() {
  if (document.getElementById('YourTextBoxId').value != txtVal) {
    alert('You changed the value.');

In your text box have code like this:

<input type="text" id="YourTextBoxId" onfocus="setVal();" onblur="checkVal();" />

Hope this helps,

Author Comment

ID: 17153755
Thanks for the code guys, I am going to use apresto's code as it runs with a single function, and call, but both answers are valid, so I am going to split the points.

Thanks again guys!
LVL 23

Expert Comment

ID: 17153802
No Problem, Glad i could help


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