Question

I have a hidden field which i want to update everytime when my textbox value is changed. It doesnt matter whether i am changing value at server side or client side when the textbox value changes hidden field should be updated. I have used onchange event of textbox but it does not work as i am changing values of textbox programatically. How can i do this?

Answer 1

You need to do it separately.

In the code behind you need to add in the TextBox_TextChanged event

HiddenField.Value = TextBox.Text

And in the client side you need to add the onchange event like onchange="javascript:updateHiddenField();" and then do something like:

function updateHiddenField() {
  document.getElementById('HiddenFieldClientID').value = document.getElementById('TextBoxClientID').value  
}

Beware that if you use MasterPages or databinding controls like repeaters/gridviews etc then the ClientID won’t be the same as the ID.