运行效果图如下：
具体代码如下：
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <meta http-equiv="Content-Language" content="zh-cn" /> <title>Javascript 表单验证</title> <body> <h3>（一）验证必填项是否有空值。</h3> <form action = "submitpage.html" onsubmit = "return validate_form(this)" method = "post"> Name:<input type = "text" name = "name" size = "20"> <input type = "submit" value = "Submit"> </form> <h3>（二）验证Email格式是否正确。</h3> <form action = "submitpage.html" onsubmit = "return is_email_form(this)" method = "post"> Email:<input type = "text" name = "email" size = "20"> <input type = "submit" value = "OK"> </form> <script> //判断内容是否为空 function validate_form(thisform){ with (thisform){ if (!validate_required(name,"Name must be filled out!")){ name.focus(); return false } } } function validate_required(field,alerttxt){ with (field){ if (value==null||value==""){ alert(alerttxt); return false }else { return true } } } //判断内容是否符合email的格式 function is_email_form(thisform){ with(thisform){ if(!checkEmail(email,"Not a valid e-mail address!")){ email.focus(); return false; } } } function checkEmail(field, alertText){ with(field){ apos = value.indexOf("@"); dotPos = value.indexOf("."); if(apos<1 || dotPos-apos<2){ alert(alertText); return false; }else{ return true; } } } </script> </body> </html>
更多关于JavaScript相关内容感兴趣的读者可查看本站专题：《JavaScript表单(form)操作技巧大全》、《JavaScript数据结构与算法技巧总结》、《JavaScript遍历算法与技巧总结》、《JavaScript中json操作技巧总结》、《JavaScript错误与调试技巧总结》及《JavaScript数学运算用法总结》