在网页表单中如何判断邮箱输入是否正确

<form name="validation" onSubmit="return checkbae()">

Please input a valid email address:<br>

<input type="text" size=18 name="emailcheck">

<input type="submit" value="Submit">

</form>

<script nguage="JavaScript1.2">

/*

Advanced Email Check credit-

By Website Abstraction (www.wsabstract.com)

Over 200+ free scripts here!

*/

var testresults

function checkemail(){

var str=document.validation.emailcheck.value

var filter=/^.+@.+\..{2,3}$/

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.all)

return checkemail()

else

return true

}

</script>