Javascript E-mail Address Validation

Please input a valid email address:

Please input a valid email address:<br />
<input type="text" size=18 name="emailcheck">
<input type="submit" value="Submit" onClick="return checkbae()">

<script language="JavaScript1.2">

var testresults
function checkemail(){
var str=document.validation.emailcheck.value
var filter=/^([\w-]+(?:\.[\w-]+)*)@((?:[\w-]+\.)*\w[\w-]{0,66})\.([a-z]{2,6}(?:\.[a-z]{2})?)$/i
if (filter.test(str))
testresults=true
else{
alert("Please input a valid email address!")
testresults=false
}
return (testresults)
}
</script>

<script>
function checkbae(){
if (document.layers||document.getElementById||document.all)
return checkemail()
else
return true
}
</script>