学习JavaScript笔记

正则实现表单验证：

charset="utf-8">

</span><span style="color: #000000;"></span></div><div><span style="color: #000088;">function</span><span style="color: #000000;"> validateForm</span><span style="color: #666600;">()</span><span style="color: #000000;"> </span><span style="color: #666600;">{</span><span style="color: #000000;"></span></div><div>    <span style="color: #000088;">var</span><span style="color: #000000;"> x </span><span style="color: #666600;">=</span><span style="color: #000000;"> document</span><span style="color: #666600;">.</span><span style="color: #000000;">forms</span><span style="color: #666600;">[</span><span style="color: #008800;">"myForm"</span><span style="color: #666600;">][</span><span style="color: #008800;">"fname"</span><span style="color: #666600;">].</span><span style="color: #000000;">value</span><span style="color: #666600;">;</span><span style="color: #000000;"></span></div><div>    <span style="color: #000088;">var</span><span style="color: #000000;"> pattern</span><span style="color: #666600;">=</span><span style="color: #008800;">/\S+/</span><span style="color: #000000;">  </span><span style="color: #880000;">//正则匹配空格等空白内容,限定符用*会出错，因为任意字串都会被匹配到</span><span style="color: #000000;"></span></div><div>    <span style="color: #000088;">if</span><span style="color: #000000;"> </span><span style="color: #666600;">(</span><span style="color: #000000;">x </span><span style="color: #666600;">==</span><span style="color: #000000;"> </span><span style="color: #000088;">null</span><span style="color: #000000;"> </span><span style="color: #666600;">||</span><span style="color: #000000;"> </span><span style="color: #666600;">!</span><span style="color: #000000;">pattern</span><span style="color: #666600;">.</span><span style="color: #000000;">test</span><span style="color: #666600;">(</span><span style="color: #000000;">x</span><span style="color: #666600;">))</span><span style="color: #000000;"> </span><span style="color: #666600;">{</span><span style="color: #000000;"></span></div><div>        alert<span style="color: #666600;">(</span><span style="color: #008800;">"需要输入名字。"</span><span style="color: #666600;">);</span><span style="color: #000000;"></span></div><div>        <span style="color: #000088;">return</span><span style="color: #000000;"> </span><span style="color: #000088;">false</span><span style="color: #666600;">;</span><span style="color: #000000;"></span></div><div>    <span style="color: #666600;">}</span><span style="color: #000000;"></span></div><div><span style="color: #666600;">}</span><span style="color: #000000;"></span></div><div><span style="color: #000088;">

name="myForm"action="demo_form.php"

onsubmit="return validateForm()"method="post">

名字: type="text"name="fname">

type="submit"value="提交">