特性检测

量多的话，推荐JS库 Modernizr

TransitonEnd


function transitionEnd(){
    var transitions = {
        'transition'       : 'transitionend',
        'WebkitTransition' : 'webkitTransitionEnd'
    };

    for(var t in transitions){
        if(document.documentElement.style[t] !== undefined){
            return transitions[t];
        }
    }
}

页面是否可见


    var vChange = '';
    var vState = '';
    
    if (typeof document.visibilityState != 'undefined') {
        vChange = 'visibilitychange';
        vState = 'visibilityState';
    } else if (typeof document.webkitVisibilityState != 'undefined') {
        vChange = 'webkitvisibilitychange';
        vState = 'webkitVisibilityState';
    }
    
    if (vChange) {
        document.addEventListener(vChange, function() {
            if (document[vState] == 'visible') {
                setTimeout(function() {
                    // 代码
                    console.log('页面可见' + Date.now())
                }, 100)
            }
        })
    }