测试一下浏览器for循环顺序不同及定义变量位置不同的效率(2)

42                 //倒序，循环内定义变量值
43                 for (var t = m; t >= 0; t--) { var temp=3; }
44
45                 d4 = new Date();
46                
47                 //倒序，循环外定义变量值
48                 for (; m >= 0; m--) { var temp=3; }
49
50                 d5 = new Date();
51
52                 return { 'r1': d2 - d1, 'r2': d3 - d2, 'r3': d4 - d3, 'r4': d5 - d4 }
53             }
54
55             //循环测试
56             function circleTest() {
57                 var str = '',
58                     result;
59
60                 result = getTestResult();
61                 str += '<tr>' +
62                        '<td>' + result.r1 + '</td>' +
63                        '<td>' + result.r2 + '</td>' +
64                        '<td>' + result.r3 + '</td>' +
65                        '<td>' + result.r4 + '</td>' +
66                        '</tr>';
67
68                 //输出结果