JS判断不能为空实例代码

复制代码 代码如下:

  <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">

  <html xmlns="http://www.w3.org/1999/xhtml">

  <head>

  <meta http-equiv="Content-Type" content="text/html"; charset="utf-8">

  <title>短信系统</title>

  <script language="javascript">

  function formcheck(){

  if(document.form.zhanghao.value==""){

  alert("号码不能为空!");

  this.form1.zhanghao.focus();

  return false;

  }else if(document.form.email.value==""){

  alert("内容不能为空!")

  this.form1.eamil.focus();

  return false;

  }else form1.submit();

  }

  </script>

  </head>

  <body>

  <form name="form" method="post" action="sendmail.php" class="formg">

  <table>

  <h2>

  <tr>

  <th colspan="8" class="CTitle">发送短信</th>

  </tr>

  </h2>

  <body>

  <tr bgcolor="#eeeeee">

  <td align="center">号   码:</td>

  <td><textarea name="content" cols="80" rows="15" id="zhanghao" class="formh"></textarea></td>

  </tr>

  <tr bgcolor="#eeeeee">

  <td align="center">内   容:</td>

  <td><textarea name="content" cols="80" rows="15" id="email" class="formh"></textarea></td>

  </tr>

  <tr bgcolor="#eeeeee" align="center">

  <td height="25" colspan="2">

  <input type="button" name="Submit" value="发 送" class="button" onClick="javascript:formcheck();">

  <input type="reset" name="Submit2" value="重 置" class="button">

  </td>

  </tr>

  </body>

  </table>

  </form>

  </body>

  </html>