I have a datepicker field setup like this and it works fine:

<input
readonly='readonly'
name='newInternalDate'
id='newInternalDate'
type='text'
value='<?php echo $perfdate;?>'
class='date date_toggled order_date'
style='background-color:rgb(210,255,210);width:85px;'
/>
I would like to raise an alert when the value is changed. I've added this:
<input
..........
onchange='alert("here");'
/>
but it doesn't work. Anyone know how to make it work please?
Thanks