You basically need to set top and left to 50% to center the left-top corner of the div. You also need to set the margin-top and margin-left ... ... <看更多>

Using the position property is one of many ways you can change the layout and positioning of an element to create unique web layouts. ... <看更多>

Also why does TweenMax.fromTo("#slide1head", 1, {backgroundPosition: "-1440px center"}, {backgroundPosition: "center center", ease: Linear ... ... <看更多>