test-for.js

test-for.js

var timers = {};
if ( console && !console.time ) {
    console.time = function( name ) {
        if ( name ) {
            timers[ name ] = Date.now();
        }
    }
    console.timeEnd = function( name ) {
        if ( timers[ name ] ) {
            console.log( name + ': ' + (Date.now() - timers[ name ]) + 'ms' );
            delete timers[ name ];
        }
    }
}

function test1(){console.time('test a');
    b = {a:{b:{c:{d:{e:{f:{g:{length:1000000}}}}}}}}
    for(var i=0; i<b.a.b.c.d.e.f.g.length; i++) ;
    console.timeEnd('test a');
}
function test2(){console.time('test b');
    b = {a:{b:{c:{d:{e:{f:{g:{length:1000000}}}}}}}}
    c = b.a.b.c.d.e.f.g.length
    for(var i=0; i<c; i++) ;
    console.timeEnd('test b');
}
for(var i=0; i<10; i++)test1()
for(var i=0; i<10; i++)test2()