瀏覽器頁面可見性事件

function getAvailableVisiablityPrfix(){
    var prefixs=['webkit','moz','ms','o'];

    if('hidden' in document)
        return '';

    for(var i=0;i<prefixs.length;i++){
        var prefix=prefixs[i];
        if((prefix+'hidden') in document){
            return prefix;
        }
    }

    //未識別到指定的結(jié)果，兜底返回
    return 'not found';
}

/**
 * 注冊頁面可見性事件
 * @param {function} hook 頁面可見性回調(diào)函數(shù)
 * @returns 
 */
function registerPageVisibilityEvent(hook){
    var prefix=getAvailableVisiablityPrfix();

    if(prefix==='not found'){
        if(window.console)
        {
            console.error('your browser is not support visibilitychange event');
        }
        else
        {
            alert('your browser is not support visibilitychange event');
        }
        return;    
    }
        
    var hiddenName=prefix+'hidden',
        eventName=prefix+ 'visibilitychange',
        stateName=prefix+ 'visibilityState';

    //注冊監(jiān)聽事件    
    document.addEventListener(
    eventName
    , function () {
        var visibilityState=document[stateName], hidden=document[hiddenName];
        hook && hook({visibilityState:visibilityState,hidden:hidden});
    }
    ,false);
}