js正则表达式验证

有时候会要验证自己写的正则表达式是否正确

所以写了这个小东西：

demo:js正则表达式验证

html:

 <h3>绿色表示匹配，红色表示不匹配</h3>
 <label>请在下框填入正则表达式</label><br />

 <textarea id="regexp"></textarea><br />

 <label>请在下框填需要验证的式子</label><br />

 <textarea id="needtest"></textarea>

css:

 #regexp,#needtest { height:100px; width:300px; resize:none; font-weight:bold;}

javascript:

 window.onload = function(){

     document.getElementById('needtest').onkeyup = function(){
         var ret = document.getElementById('regexp').value;
         ret = '^' + ret + '$';
         var re = new RegExp(ret)

         if(re.test(document.getElementById('needtest').value)){

             document.getElementById('needtest').style.color = 'green';
         }else{
             document.getElementById('needtest').style.color = 'red';
         }
     }

     document.getElementById('regexp').onkeyup = function(){
         var ret = document.getElementById('regexp').value;
         ret = '^' + ret + '$';
         var re = new RegExp(ret)

         if(re.test(document.getElementById('needtest').value)){

             document.getElementById('needtest').style.color = 'green';
         }else{
             document.getElementById('needtest').style.color = 'red';
         }
     }

 }