JS内置对象

字符串对象

<script>
     //字符串对象
       var str = "Hello worldlsgjlsjg";
       document.write('string.length='+str.length);
     //查找索引
       document.write("<br/>indexof 'wor'",+str.indexOf('wor'));
    //字符串匹配
       document.write("<br/>mathch world————》"+str.match('world'));
     //字符串替换
       document.write('<br/>replace--->'+str.replace("Hello","RIRIR"));
      //字符串转换为数组
      var strArray = str.split(' ');
      document.write('<br/>strArray[0]='+strArray[0]);
</script>

日期对象

/*------日期对象------*/
      document.write('<br/>日期对象<br/>');
//    获取当前日期
      var date = new Date();
      document.write('<br/>date:'+date);
//    获取年份
      document.write("<br/>"+date.getFullYear())
      //获取当前时间戳
      document.write("<br/>时间戳:"+date.getTime());
      //创建自定义日期
      date.setFullYear(2016,1,1);
      document.write("<br/>自定义的时间:"+date);

　数组对象

  /*------数组对象------*/
//     数组合并
       var a =["Hello","world"];
       var b = ["lin","iw"];
       var c =a.concat(b);
       document.write("<br/>数组合并:"+c);

//     数组排序
       var arry = ["a","b","c","b","a","f","e"];
       var numArray = [21,4,1,5,25,9,38,4];
       //升降序
       function compareFunc(a,b){
       	return b-a;
       }
       document.write("<br/>数组排序"+arry.sort());
       document.write("<br/>数组升降序排序"+numArray.sort(compareFunc));
//     数组追加值
       arry.push("zhuijia");
       document.write("<br/>数组追加"+arry);

//     数组翻转
       document.write("<br/>数组翻转"+numArray.reverse());

Math对象

  /*------Math对象------*/
     document.write("<br/>四舍五入:"+Math.round(2.5));
//   随机数
     document.write("<br/>随机数:"+parseInt(Math.random()*10));
   //求最大值
     document.write("<br/>求最大值:"+Math.max(1,2.4325,525,53,5))
    //求绝对值
     document.write("<br/>求绝对值:"+Math.abs(-10));