The onSelect event handler is fired when the text in the area is highlighted.
<html> <head> <script language="JavaScript"> <!-- function setText(){ document.myForm.myTextArea2.value = document.myForm.myTextArea1.defaultValue; } --> </script> </head> <body> <form name="myForm"> <textarea name="myTextArea1" rows=2 cols=50 onSelect='setText()'> Here is some text in my text area. </textarea> <br> <textarea name="myTextArea2" rows=2 cols=50> </textarea> </form> </body> </html>