javascript 基础2第12节

<html>
	<head>
	<title>javascript基础</title>
	</head>
	
	<body>		

		1.Number</br>
		<script type="text/javascript">
			 var  ia  = 10;//基本类型  typeof
			 var  name = '张三';
			 var  married = false;


			 var oNum = new Number(10);
			 var oName = new String('张三');

			 document.write("typeof ia :  " ,typeof ia,"<br/>");

			  document.write("typeof name :  " ,typeof name,"<br/>");
			  document.write("name.toString() :  " , name.toString(),"<br/>");//伪对象

			  document.write("typeof oName :  " ,typeof oName,"<br/>");
			 document.write("typeof oNum :  " ,typeof oNum,"<br/>");
			//对象类型检测  instanceof
			 document.write("oNum instanceof Number :  " , oNum instanceof Number,"<br/>");
			 document.write("ia == oNum :  " ,ia == oNum,"<br/>");
			 document.write("ia === oNum :  " ,ia === oNum,"<br/>");


			 var  ob = Number('123');//基本类型
			 document.write("typeof ob :  " ,typeof ob,"<br/>");
			 document.write("ob :  " , ob,"<br/>");
			  document.write("Number.MAX_VALUE :  " , Number.MAX_VALUE,"<br/>");
			document.write("Number.MIN_VALUE :  " , Number.MIN_VALUE,"<br/>");
			
			var ib = 3.148592654233789;  //new Number();
			document.write("ib :  " , ib,"<br/>");
			document.write("ib.toFixed(2) :  " , ib.toFixed(2),"<br/>");
		</script>     	
		2.Boolean</br>
		<script type="text/javascript">
			
			document.write("Boolean(5) :  " , Boolean(5),"<br/>");
			document.write("Boolean(null) :  " , Boolean(null),"<br/>");
			document.write("Boolean('a') :  " , Boolean('a'),"<br/>");
		</script>     	

		3.String</br>
		<script type="text/javascript">
			var  str = "Hello World Hello JavaScript  I like jaVAScript you like JAVAscript"; 
			document.write("str :  " , str,"<br/>");
			document.write("str属性length :  " , str.length,"<br/>");
			document.write("str.toUpperCase() :  " , str.toUpperCase(),"<br/>");
			document.write("str.toLowerCase() :  " , str.toLowerCase(),"<br/>");
			document.write("str.charAt(0) :  " , str.charAt(0),"<br/>");
			document.write("str.charAt(X) :  " , str.charAt(str.length-1),"<br/>");

			document.write("str.charCodeAt(19) :  " , str.charCodeAt(19),"<br/>");
			document.write("str.concat(10,'abcd',true) :  " , str.concat(10,'abcd',true),"<br/>");
			document.write("String.fromCharCode(97) :  " , String.fromCharCode(97),"<br/>");
			//查找
			document.write("str.indexof('java') :  " , str.indexOf('java'),"<br/>");
			document.write("str.indexof('java') :  " , str.toLowerCase().indexOf('java'),"<br/>");

			document.write("str.indexof('java',20) :  " , str.toLowerCase().indexOf('java', 20),"<br/>");

			document.write("str.lastIndexof('java') :  " , str.toLowerCase().lastIndexOf('java'),"<br/>");
			//截取
			document.write("str.slice(6,11) :  " , str.slice(6,11),"<br/>");
			document.write("str.substr(6,5) :  " , str.substr(6,5),"<br/>");
			document.write("str.substring(6) :  " , str.substring(6),"<br/>");
			var data = "2014-7-28";
			var arr = data.split('-');//字符串数组
			document.write("arr[0] :  " , arr[0],"<br/>");
			document.write("arr[1] :  " , arr[1],"<br/>");
			document.write("arr[2] :  " , arr[2],"<br/>");
		</script>     	
	</body>

</html>
2.结果：