<html> <head> <script language="javascript"> function hello(){ alert('Xin chào !'); } var x = setInterval(hello, 3000); function clearTime(){ clearInterval(x); document.write('đã hủy setInterval()'); } </script> </head> <body> <input type="button" onclick="clearTime()" value="Hủy Time Out" /> </body> </html>