如何使javascript聊天轮询脚本更高效?

出于某种原因,这种对新聊天信息的检查会导致比我预期的更多的浏览器(在某种程度上是服务器)负载。有人知道我有什么办法能让它更有效,减轻负担吗?

// Begin the cycle of refreshing the mini chat after the standard delay.
function startRefreshingMinichat(){
    var secs = 30; // Chat checking frequency.
    setTimeout(function (){
        checkForNewChats();
        startRefreshingMinichat(); // Loop the check for refresh.
    }, secs*1000);
}

// Check for the latest chat and update if it's different.
function checkForNewChats(){
    // Check whether the latest chat doesn't match the latest displayed chat.
    // NOTE THAT THIS CALLBACK DOES NOT TRIGGER IMMEDIATELY.
    $.getJSON('api.php?type=latest_chat_id&jsoncallback=?', function(data){
        var newChats = false;
        // Update global data stores if an update is needed.
        if(updateDataStore(data.latest_chat_id, 'chat_id', 'latestChatId', 'chat_id')){
            newChats = true;
        }
        if(newChats){ // there are new chats to show.
            refreshMinichat(null, 50); // loads new chat content.
        }
        // Since this callback isn't immediate, any feedback has to occur whenever the callback finishes.
 }); // End of getJSON function call.
}