js字符串替换

   var text=\'Hello world, Hello world\';
   var b= text.replace(\'world\',\'zhengxiaoya\');  // 找到字符串中的第一个\'world\',并把它替换为\'zhengxiaoya\'
   var c=text.replace(/world/g,\'zhengxiaoya\');   // 用正则表达式去匹配所有的\'world\',替换为\'zhengxiaoya\'
    var d=text.replace(/hello/gi,\'Hi\')           // 忽略大小写替换所有匹配
   console.log("---today---",b);                // ---today--- Hello zhengxiaoya, Hello world
   console.log("---today c---",c);              // Hello zhengxiaoya, Hello zhengxiaoya
   console.log("---d----",d);                  //---d---- Hi world, Hi world