代码如下：
<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"> 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>