<html> <head> <title>E-mail Example</title> <script type="text/javascript"> function isValidEmail(sText) { var reEmail = /^(?:\w+\.?)*\w+@(?:\w+\.)+\w+$/; return reEmail.test(sText); } function validate() { var oInput1 = document.getElementById("txt1"); if (isValidEmail(oInput1.value)) { alert("Valid"); } else { alert("Invalid!"); } } </script> </head> <body> <P>E-mail Address: <input type="text" id="txt1" /><br /> <input type="button" value="Validate" onclick="validate()" /></p> </body> </html>