源代码 ：
点击运行
<!DOCTYPE html> <html> <head> <meta charset="utf-8"> <title>开源教程(ossoft.cn)</title> </head> <head> <script> function validateForm(){ var x=document.forms["myForm"]["email"].value; var atpos=x.indexOf("@"); var dotpos=x.lastIndexOf("."); if (atpos<1 || dotpos<atpos+2 || dotpos+2>=x.length){ alert("不是一个有效的 e-mail 地址"); return false; } } </script> </head> <body> <form name="myForm" action="demo-form.php" onsubmit="return validateForm();" method="post"> Email: <input type="text" name="email"> <input type="submit" value="提交"> </form> </body> </html>
运行结果