javascript中使用正则表达式进行字符串验证示例

!DOCTYPE html>
html>
head>
title>testTablel.html/title>
!-- 用户名，不能为空
密码6为数字
密码确认，两次输入密码必须相同
身份证号码必须是15位，或者是18位，最末尾也可以是X -->
style>
#d1 {
width: 400px;
height: 250px;
background-color: #FFE4B5;
margin: 40px auto;
}
#d1_head {
color: white;
font-size: 20px;
font-family: "Arial";
height: 24px;
background-color: bule;
}
#d1_content {
padding-left: 30px;
padding-top: 30px;
}
.s1 {
color: red;
font-style: italic;
}
.s2 {
border: 2px dotted blue;
}
/style>
meta http-equiv="content-type" content="text/html; charset=UTF-8">
script>
function check_username(){
var txtObj=document.getElementById("username");
txtObj.className='';
var msgObj=docuemnt.getElementById("username_msg");
msgObj.innerHTML='';
if(txtObj.value.length==0){
msgObj.innerHTML='用户名不能为空';
//给节点的class属性赋值
txtObj.className='s2';
return false;
}
return true;
}
function check_pwd(){
var pwdObj=document.getElementById("pwd");
pwdObj.classNames='';
var msgObj=document.getElementById("pwd_msg");
msgObj.innerHTML='';
var reg=/^\d{6}$/;
//javascript中一个test方法，返回boolean
if(!reg.test(pwdObj.value)){
msgObj.innerHTML='密码是6位数';
pwdObj.className='s2';
return false;
}
return true;
}
function check_pwd1(){
var pwdObj=document.getElementById("pwd");
// pwdObj.classNames='';
// var msgObj=document.getElementById("pwd_msg");
// msgObj.innerHTML='';
var pwdObj1=document.getElementById("pwd1");
//pwdObj1.classNames='';
var msgObj1=document.getElementById("pwd_msg1");
msgObj1.innerHTML='';
if(pwdObj.value!=pwdObj1.value){
msgObj1.innerHTML='密码不一致，请重新输入';
return false;
}
return true;
}
function check_form(){
var flag=check_username()check_pwd()check_pwd1;
return flag;
}
/script>
/head>
body>
div id="d1">
div id="d1_head">注册/div>
div id="d1_content">
form onsubmit="return check_form();">
table>
tr>
td>用户名/td>
td>input id="username" name="username"
onblur="check_username();" /> span class="s1" id="username_msg">/span>
/td>
/tr>
tr>
td>密码/td>
td>input type="password" id="pwd" name="pwd"
onblur="check_pwd();" /> span class="s1" id="pwd_msg">/span>/td>
/tr>
tr>
td>确认密码/td>
td>input type="password" id="pwd1" name="pwd1"
onblur="check_pwd1();" /> span class="s1" id="pwd_msg1">/span>
tr>
td colspan="2">
input type="submit" value="确认" /> input type="reset"
value="重置" />
/td>
/tr>/table>
/form>
/div>
/div>
/body>
/html>