使用JavaScript进行表单校验功能

<script>
function validateUsername(){ 
var input = document.myform.userName.value; 
if(input == “”||input == null) { 
document.myform.userName.focus(); 
document.getElementById(“uname”).innerHTML=”用户名不能为空!”; 
return false; 
} 
else if(input.length>5 || input.length<2){ 
document.getElementById(“uname”).innerHTML= “用户名在2~5位”; 
document.myform.userName.focus(); 
return false; 
} 
else{ 
document.getElementById(“uname”).innerHTML=”“; 
return true; 
} 
} 
function validatePassword(){ 
var password = document.myform.password.value;
if(password == “”||password == null) { 
document.getElementById(“upss”).innerHTML = “密码不能为空!”; 
document.myform.password.focus(); 
return false;
} 
else if(password.length>12 || password.length<6){ 
document.getElementById(“upss”).innerHTML= “密码在6~12位”; 
document.myform.password.focus(); 
return false; 
} 
else{ 
document.getElementById(“upss”).innerHTML= “”; 
return true; 
} 
} 
function validatePasswordAgain(){ 
var psw = document.myform.psw.value; 
var password = document.myform.password.value; 
if(psw!=password){ 
document.getElementById(“upssa”).innerHTML=”两次密码输入不同”; 
return false; 
}else{ 
document.getElementById(“upssa”).innerHTML = “”; 
return true; 
} 
} 
function validateGroup(){ 
var select = document.getElementById(“select”); 
if(select.value == “NONE”){ 
document.getElementById(“groupID”).innerHTML=”请选择分组!”;
return false; 
}else { 
document.getElementById(“groupID”).innerHTML=”“;
return true; 
} 
} 
function validateForm(){ 
var flag = validateUsername()&&validatePassword()&&validatePasswordAgain()&&validateGroup(); 
if(flag){ 
return true; 
}else return false; 
}

<div class="warp"> 
<h1>新用户注册</h1>
<form action="/myproject/admin/addUser" name="myform" onsubmit="return validateForm()">
<div class="form-warp">  
 <ul>
  <li>用户名称<input class="input" type="text" name="userName" placeholder="请输入..." onblur="validateUsername()"/></li>
  <li>密 码<input class="input" type="password" name="password" id="password" placeholder="请输入..." onblur="validatePassword()"/></li>
  <li>确认密码<input class="input" type="password" name="psw" id="psw" placeholder="请输入..." onblur="validatePasswordAgain()"/></li>
  <li>真实姓名<input class="input" type="text" name="realName" placeholder="请输入..."/></li>
  <li>分 组<select name="group.id" id="select" onblur="validateGroup()">
     <option value="NONE">请选择...</option>
     <#list groups as group>
      <option value="${group.id}">${group.name}</option>
     </#list>
     </select>
  </li>
  <li><input type="submit" value="提交" id="button"/></li>
 </ul>
<ul class="validate">
 <li id="uname"></li>
 <li id="upss"></li>
 <li id="upssa"></li>
 <li id="groupID"></li>
</ul>
</div>
</form>
</div>
“`