## JavaScript basis (b)

JavaScript basis (b)

　　 ## a, in peace we need to verify whether the book output to meet the requirements, then the figures how to solve:

 

< Body > 
< H2 > the JavaScript can verify input </ H2 > 
< P > Please enter a number between 1 and 10: </ P > 
< INPUT ID = "Numb" > 
< Button type = "Button" the onclick = "myFunction () " > submit </ Button > 
< P ID =" Demo " > </ P > 
< Script > 
function myFunction () {
   var X, text;
  // Gets the value of id = "numb" in the input field
  x = document.getElementById ( " Numb " ) .Value;
   // if x is not less than 1 or greater than or number 10 
  IF (isNaN (x) || x <  1  || x >  10 ) { 
    text =  " Invalid input " ; 
  } the else { 
    text =  " enter valid " ; 
  } 
  document.getElementById ( " Demo " ) .innerHTML = text; 
} 
</ Script > 
</ body>

 

　　## Second, the registration page, enter how to verify compliance with the requirements of:

<tr>
   <td class="td_left"><label for="username">用户名:</label></td>
   <td class="td_right"><input type="text" name="username" id="username" placeholder="请输入用户名" onblur="checkUserName()">
   <span id="s_username"class="error"style="color: red"></span>
   </td>
 </tr>
 <tr>
    <td class="td_left"><label for="password">密码:</label></td>
    <td class="td_right"><input type="password" name="password" id="password" placeholder="请输入密码"onblur="checkPassWord()">
    <span id="s_password"class="error"></span>
    </td>
  </tr>

　　So we javaScript code in the method:

<script type="text/javascript">
    function checkUserName() {
        var username=document.getElementById("username").value;//获得username id的对象
        var reg_username=/^\w{6,12}$/;
        var flag=reg_username.test(username);
        var s_username=document.getElementById("s_username");
        if(flag){
            s_username.innerHTML="<img src='gou.png'>";
        }else{
            s_username.innerHTML="用户名格式错误";
        }
    }
    function checkPassWord() {
        var password=document.getElementById("password").value;
        var reg_password=/^\w{6,12}$/;
        var flag=reg_password.test(password);
        var s_password=document.getElementById("s_password");
        if(flag){
            s_password.innerHTML="<img src='gou.png'>";
        }else{
            s_password.innerHTML="密码格式错误，请重新输入";
        }
    }
</script>