Js定数と変数

    


    

    

        
            //1.  ：    、   、   、null……
            document.write("<li>JavaScript  ，tomy   ！");
            document.write("<li>" + 3 + "   !");
            if(true)
            {
                document.write("<li>if          ：" + true);
            }
            document.write("<li>       011      ：" +　011);
            document.write("<li>        0xf      ：" + 0xf);
            //  ：        
            //var     =  ；    //    
            //    =  ；        //  
            //var js         ，         ！
            // var            
            //var    ；
            
            //var str = "js  ，    !";      //        
            //var b = true;                       //       
            //var n = 10;                         //     
            //var obj = new Object();             //     
            
            //  
            var str = "tomy   js!";
            var b = true;
            var n = 10;
            var m;
            var o = new Object();
                p = new Object();
            document.write( "<hr>" + str + "<br>");
            document.write( b + "<br>");
            document.write( n + "<br>");
            document.write( m + "<br>");
            document.write( o + "<br>");
            document.write( p + "<br>");
            //       
            alert("       ");
            str = "       ";
            b = false;
            n = 20;
            m = 30;
            o = new Array("data1","data2");        //o         
            document.write("<font color=red><br>");
            document.write( "<hr>" + str + "<br>");
            document.write( b + "<br>");
            document.write( n + "<br>");
            document.write( m + "<br><br>");
            document.write( o + "<br>");
            document.write( "  o    ：" + o.length + "<br>");
            document.write(p + "<br>");
            document.write("<br></font>");
            var pp;
            document.write(pp);
            var pp = 20;//       ，   
            
            //       ：
            //         ，         ，        
            //     
            //name Name    
            //       ，          s，       n……
            //var sMyStr ="my string";
            //var nIndex = 0;
            
            var nA = 10;
            var nB = 20;
            document.write("<hr>   <br>");
            document.write("<li>nA = " + nA);
            document.write("<li>nB = " + nB);
            var nTemp = nA;
            nA = nB;
            nB = nTemp;
            document.write("<br>   <br>");
            document.write("<li>nA = " + nA);
            document.write("<li>nB = " + nB);
            
            //       
            //
            function func()
            {
                var nA = 999;//  ！:             ，       var   
                document.write("<li>      nA:" + nA);
            }
            func();
            document.write("<li>      nA:" + nA);
            
            //     
            var actorAry = new Array("cpu","  ","  ");
            document.write("<hr>    ：");
            for(n in actorAry)           //    
            {
                document.write("<li>" + actorAry[n]);//  actorAry        
            }