JavaScript中变量声明效率问题

 1 var theString1 = "字符串1";
 2 var theString2 = "字符串1";
 3 var theString3 = "字符串1";
 4 var theString = {
 5 　　theString1: "字符串1",
 6 　　theString2: "字符串1",
 7 　　theString3: "字符串1",
 8 }
 9 
10 var time1 = new Date();
11 for(var i =0; i<100000000; i++){
12 　　var thisString = theString1 + theString2 + theString3;
13 }
14 var time2 = new Date();
15 console.log(" 变量(time2-time1)--->",(time2-time1));
16 
17 var time3 = new Date();
18 for(var i =0; i<100000000; i++){
19 　　var thisString = theString.theString1 + theString.theString2 + theString.theString3;
20 }
21 var time4 = new Date();
22 console.log(" 变量(time4-time3)--->",(time4-time3));
23 //输出结果:
24 变量(time2-time1)---> 1387
25 变量(time4-time3)---> 1465