JavaScript实现密码框显示与隐藏切换功能

<html>
  <head>
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
  </head>
  <body>
    <form method="POST" action="" name="forms">
      <span id=box><input type="password" name="password" size="80" style="width:150;" value="sina.com"></span>
      <span id=click><a href="javascript:showps()">显示密码</a></span>
    </form>
  </body>
 <script language="JavaScript">
    function showps(){
     if (this.forms.password.type="password") {
      document.getElementById("box").innerHTML="<input type=\"text\" name=\"password\" size=\"80\" style='width:\"150\";' value="+this.forms.password.value+">";
      document.getElementById("click").innerHTML="<a href=\"javascript:hideps()\">隐藏密码</a>"
     }
    }
    function hideps(){
     if (this.forms.password.type="text") {
      document.getElementById("box").innerHTML="<input type=\"password\" name=\"password\" size=\"80\" style='width:\"150\";' value="+this.forms.password.value+">";
      document.getElementById("click").innerHTML="<a href=\"javascript:showps()\">显示密码</a>"
     }
    }
 </script>
</html>