javascript常用对象
1.Date对象：
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <title> New Document </title> <meta name="Generator" content="EditPlus"> <meta name="Author" content=""> <meta name="Keywords" content=""> <meta name="Description" content=""> <script type="text/javascript"> var date = new Date(); document.write(date); </script> </head> <body> </body> </html>
运行结果：
我们来改变一下输出的方式：
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <title> New Document </title> <meta name="Generator" content="EditPlus"> <meta name="Author" content=""> <meta name="Keywords" content=""> <meta name="Description" content=""> <script type="text/javascript"> var date = new Date(); document.write(date.getFullYear()+"年"+date.getMonth()+"月"+date.getDate()+"日"); </script> </head> <body> </body> </html>
运行结果：
明明是9月，却显示的是8月，说明getMonth是从下标0开始的，所以要加1：
document.write(date.getFullYear()+"年"+(date.getMonth()+1)+"月"+date.getDate()+"日");
这样就会输出正确的结果了。
2.String对象：
2.1
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<title> New Document </title>
<meta name="Generator" content="EditPlus">
<meta name="Author" content="">
<meta name="Keywords" content="">
<meta name="Description" content="">
<script type="text/javascript">
var str1 = new String("niujiabin");
var str2 = "niujiabin";
alert(str1==str2);
</script>
</head>
<body>
</body>
</html>
结果是true，这里与java是有区别的，并不存在引用，没有equals方法。
2.2字符串连接
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<title> New Document </title>
<meta name="Generator" content="EditPlus">
<meta name="Author" content="">
<meta name="Keywords" content="">
<meta name="Description" content="">
<script type="text/javascript">
var str1 = new String("niujiabin");
var str2 = "niujiabin";
// alert(str1==str2);
//字符串的连接
var str3 = str2.concat("maybe","gossip");
alert(str3);
</script>
</head>
<body>
</body>
</html>
连接字符串，concat的参数没有限制，随便连就可以了，输出结果：
2.3字符串截取
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <title> New Document </title> <meta name="Generator" content="EditPlus"> <meta name="Author" content=""> <meta name="Keywords" content=""> <meta name="Description" content=""> <script type="text/javascript"> //字符串截取 var str1 = "niujiabinbin"; var str2 = str1.slice(3,6); alert(str2); </script> </head> <body> </body> </html>
运行结果：
2.4字符串选取substring与substr
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <title> New Document </title> <meta name="Generator" content="EditPlus"> <meta name="Author" content=""> <meta name="Keywords" content=""> <meta name="Description" content=""> <script type="text/javascript"> var str1 = "niujiabinbin"; document.write(str1.substring(2,9)+"<br>"); document.write(str1.substr(2,9)); </script> </head> <body> </body> </html>
运行结果：
区别在于substring是下标2-9，而substr是从下标2开始，选取9个字符。
3.array对象：
js中的array对象其实就是java中的List和Stack集合
3.1
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<title> New Document </title>
<meta name="Generator" content="EditPlus">
<meta name="Author" content="">
<meta name="Keywords" content="">
<meta name="Description" content="">
<script type="text/javascript">
//第一种定义方式
var a1 =new Array();
a1.push(11);
a1.push(12);
document.write(a1+"<br>");
//第二种定义方式
var a2 = new Array("niujiabin","1",1);
document.write(a2+"<br>");
//第三种定义方式,一般都采用这种方式
var a3=["maybe",1,"1"];
document.write(a3+"<br>");
</script>
</head>
<body>
</body>
</html>
输出结果：
输出结果的分割形式都是逗号，我们当然也可以改变，只需通过join方法：
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<title> New Document </title>
<meta name="Generator" content="EditPlus">
<meta name="Author" content="">
<meta name="Keywords" content="">
<meta name="Description" content="">
<script type="text/javascript">
//第一种定义方式
var a1 =new Array();
a1.push(11);
a1.push(12);
document.write(a1.join("-")+"<br>");
//第二种定义方式
var a2 = new Array("niujiabin","1",1);
document.write(a2.join("_")+"<br>");
//第三种定义方式,一般都采用这种方式
var a3=["maybe",1,"1"];
document.write(a3.join("***")+"<br>");
</script>
</head>
<body>
</body>
</html>
运行结果：
3.2 sort方法：
这个方法只会根据字符串来排序：
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <title> New Document </title> <meta name="Generator" content="EditPlus"> <meta name="Author" content=""> <meta name="Keywords" content=""> <meta name="Description" content=""> <script type="text/javascript"> var a3=[1111,111,12,443,44,555,5555,67,76]; document.write(a3.sort()); </script> </head> <body> </body> </html>
排序结果：
array的方法还有pop，shift，onshift等对栈和队列的相关操作，还有splice插入元素，这里就不一一介绍了。