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';
        }
    }
    
}