Attribute for `<TEXTAREA ...>`
`onChange = "script command(s)"`

Usage Recommendation
use it, but don't rely on it

onChange is triggered when the user changes the value of the text area. It occurs after the user moves the cursor out of the field, not while the user types. If you want to run a script for every key press you may want to look at onKeyPress.

onChange can be used to modify the value of the text area after the users fills out the field. For example, suppose we want reset the field to completely upper case. First we would put a script like the following into the <HEAD> section of the page:

<SCRIPT TYPE="text/javascript">
<!--
function setupper(myfield)
{
if (myfield.inchange)return;
myfield.inchange=true;
myfield.value=myfield.value.toUpperCase();
myfield.inchange=false;
}
//-->
</SCRIPT>

This script accepts a field object as input, the resets the value of the field to upper case. We can then call the script in the onChange attribute like this:

<TEXTAREA ROWS=10 COLS=20 NAME="IDlist" 
   onChange="setupper(this)"
   ></TEXTAREA>

Notice that the one argument for the script is this, meaning that the field passes itself as the argument. This gives us the following form. Type something into the text area, then click in the next field.

Attribute for <TEXTAREA ...> onChange = "script command(s)"

Attribute for `<TEXTAREA ...>`
`onChange = "script command(s)"`