javascript - Prototype JS 框架 - 当定期更新程序发生更新时调用函数

Question

如何在每次更新时调用函数？以下是我尝试过的。这不起作用。当我单独执行时，该函数本身运行良好。

new Ajax.PeriodicalUpdater('chatMessages', 'chat/receive_chat',
        {
                method: 'post',
                parameters: {lId: latestId},
                insertion: Insertion.Bottom,
                frequency: 2,
                decay: 2,
                Onsuccess: val = function(){$('chatMessages').scrollTop = $('chatMessages').scrollHeight;}
        });

Answer 1

这是一个工作示例:JSFiddle Example

var msgCount = 0;

new Ajax.PeriodicalUpdater('chatMessages', '/echo/html/', {
    insertion: Insertion.Bottom,
    frequency: 2,
    decay: 2,
    onSuccess: function() {
        msgCount++;
        var response = '<div class="msg">Message '+msgCount+'</div>';
        response += '<div>'+bigLongString+'</div>';
        $('chatMessages').innerHTML += response;
        $('chatMessages').scrollTop = $('chatMessages').scrollHeight;
    }
});


var bigLongString = "Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem Ipsum has been the industry's standard dummy text ever since the 1500s, when an unknown printer took a galley of type and scrambled it to make a type specimen book. It has survived not only five centuries, but also the leap into electronic typesetting, remaining essentially unchanged. It was popularised in the 1960s with the release of Letraset sheets containing Lorem Ipsum passages, and more recently with desktop publishing software like Aldus PageMaker including versions of Lorem Ipsum."