replace

<!DOCTYPE html>
<html>
<head>
  <meta charset="UTF-8">
  <title>hh</title>
  <style type="text/css">
  </style>
  <script language="JavaScript">
          var str="Paul,Paula,paul,sPaul,Paul";
         var strNew=str.replace(/Paul/g,"Ringo");
         alert(strNew);
  </script>
</head>
<body>

</body>
</html>

参考与脚本之家