• javascript 基础2第12节


    1.

    <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:

    3.

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  • 原文地址:https://www.cnblogs.com/feilongblog/p/4739577.html
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