Simple scroll problem

Hi there Kirupians!

I’ve got a simple problem and I can’t remember how to fix this.
I have a textField with text greater than the field.
Below this textField I have two buttons. scroll_down_btn and scroll_up_btn.
These buttons scroll the text once they’re pressed.
[AS]on(press){
textField.scroll =+1
}[/AS]

But how do I have to change my code so that as long as the user holds the mouse down over the button, the text keeps on scrolling?
In the current situation the user has to click the button for each line he/she wants to scroll.

Can anybody help me?