javascript学习笔记(六):对象、内置对象

创建对象

对象属性赋值的方式

 1 <!DOCTYPE html>
 2 <html>
 3 <head lang="en">
 4     <meta chaset="UTF-8">
 5     <title></title>            
 6 </head>    
 7 <body>
 8     <script>
 9         people = new Object();     //javascript对象的创建
10         
11         //对people对象属性赋值第一种方式
12         people.name = "jerry";      //对people对象的name属性赋值
13         people.age = "18";           //对people对象的age属性赋值
14         document.write("name:"+people.name+",age:"+people.age+"</br>");
15         
16         //对people对象属性赋值第二种方式
17         people = {name:"tom",age:"15"};//对people对象的name属性、age属性赋值
18         document.write("name:"+people.name+",age:"+people.age);
19 
20     </script>
21 </body>
22 </html>

创建自定义对象

 1 <!DOCTYPE html>
 2 <html>
 3 <head lang="en">
 4     <meta chaset="UTF-8">
 5     <title></title>            
 6 </head>    
 7 <body>
 8     <script>
 9         //自定义对象的创建
10         //使用函数来创建对象,然后创建对象实例
11         function people(name,age){
12             this.name = name;
13             this.age = age;
14         }
15         son = new people("tom",30);
16         document.write("name:"+son.name+",age:"+son.age);
17     </script>
18 </body>
19 </html>

javascript内置对象

string对象

 1 <!DOCTYPE html>
 2 <html>
 3 <head lang="en">
 4     <meta chaset="UTF-8">
 5     <title></title>            
 6 </head>    
 7 <body>
 8     <script>
 9         var str = "Hello World";
10         document.write("字符串长度:"+str.length+"</br>");
11         document.write("查询字符串的位置:"+str.indexOf("World")+"</br>");
12         document.write("匹配字符串是否存在,若存在输出这个字符,若不存在输出空:"+str.match("World")+"</br>")
13         document.write("替换字符串:",str.replace("World","javascript")+"</br>");
14         document.write("字符串转换成大写:"+str.toUpperCase()+"</br>");
15         document.write("字符串转换成小写:"+str.toLowerCase()+"</br></br>");
16         
17         var str1 = "Hello,tom,jerry,gophi";
18         document.write("字符串:"+str1+"</br>");
19         var s = str1.split(",");
20         document.write("字符串分割之后的结果:</br>");
21         document.write(s[0]+"</br>");
22         document.write(s[1]+"</br>");        
23         document.write(s[2]+"</br>");
24         document.write(s[3]+"</br>");    
25     </script>
26 </body>
27 </html>

date对象

 1 <!DOCTYPE html>
 2 <html>
 3 <head lang="en">
 4     <meta chaset="UTF-8">
 5     <title></title>            
 6 </head>    
 7 <body>
 8     <script>
 9         var date = new Date();
10         document.write("时间:"+date+"</br>");       //获取时间总信息
11         document.write(+date.getFullYear()+"年</br>");  //获取年份
12         document.write("星期"+date.getDay()+"</br>");   //获取星期几
13         document.write("时间戳:"+date.getTime()+"</br>");//获取时间戳
14         date.setFullYear(2000,1,1)             //设置时间
15         document.write("设置时间为:"+date+"</br>");    //获取时间总信息        
16     </script>
17 </body>
18 </html>

一个简单的时钟程序

 1 <!DOCTYPE html>
 2 <html>
 3 <head lang="en">
 4     <meta chaset="UTF-8">
 5     <title></title>            
 6 </head>    
 7 <body onload="startTime()"> <!--用一个onload事件调用startTime函数-->
 8     <script>
 9         function startTime(){
10             var today = new Date();
11             var h = today.getHours();    //获取时
12             var m = today.getMinutes();    //获取分
13             var s = today.getSeconds(); //获取秒
14             m = checkTime(m);
15             s = checkTime(s);
16             
17             document.getElementById("timetxt").innerHTML = h+":"+m+":"+s;
18             t = setTimeout(function(){startTime();},1000);      //每1000毫秒刷新一次时间
19             //checkTime函数的作用是使分、秒为个位数时仍输出两位,比如9分5秒,输出09:05                
20         }
21         function checkTime(i){
22             if(i<10){
23                 i = "0" + i;
24             }
25             return i;
26         }
27     </script>
28     <div id="timetxt"></div>            <!--设置一个显示时间的标签-->    
29 </body>
30 </html>

array对象

 1 <!DOCTYPE html>
 2 <html>
 3 <head lang="en">
 4     <meta chaset="UTF-8">
 5     <title></title>            
 6 </head>    
 7 <body> 
 8     <script>
 9         //concat():合并数组
10         var a=["hello","world"];
11         var b=["tom","jerry"];
12         var c=a.concat(b);
13         document.write(c+"</br>");
14         
15         //sort():排序
16         var aa=["a","e","c","v","b"];
17         document.write(aa.sort()+"</br>");
18         
19         var bb=[1,9,2,3,4,7,8,5];
20         document.write(bb.sort()+"</br>");
21         
22         //push():末尾追加元素
23         var cc=["a","b"];
24         cc.push("c");
25         document.write(cc+"</br>");
26         
27         //reverse():数组元素翻转
28         var dd=["1","2","3","4","5"];
29         document.write(dd.reverse());
30         
31     </script>        
32 </body>
33 </html>

math对象

 1 <!DOCTYPE html>
 2 <html>
 3 <head lang="en">
 4     <meta chaset="UTF-8">
 5     <title></title>            
 6 </head>    
 7 <body> 
 8     <script>
 9         //round(),四舍五入
10         document.write(Math.round(2.5)+"</br>");
11         //random(),0~1之间的随机数        
12         document.write(Math.random()+"</br>");
13         //parseInt(),取整
14         document.write(parseInt(Math.random()*10)+"</br>");//求0~10之间的随机整数
15         //max(),求最大值
16         document.write(Math.max(10,2000,1,35,6.7,-10)+"</br>");
17         //min(),求最小值
18         document.write(Math.min(10,2000,1,35,6.7,-10)+"</br>");
19         //abs(),求绝对值
20         document.write(Math.abs(-10));
21     </script>        
22 </body>
23 </html>
原文地址:https://www.cnblogs.com/zylq-blog/p/7002235.html