<html><head><title>Finding the absolute value</title><script language="javascript" type="text/javascript"><!--function f(){ var myVar = prompt("A number", ""); var theModulus = (myVar>=0)? myVar: -myVar; var msg = (isNaN(theModulus))? "Numbers only.": "The modulus of " + myVar + " is " + theModulus; alert(msg);}//--></script></head><body><h1>Finding the absolute value</h1><a href="javascript:f()">Get absolute value</a></body></html>