Question

I have a problem with this code:

setInterval(function() {
        var timed = $("#chMsgCont").find(".chatMsg:last-child");
        var timee = timed.attr("data");
        $.ajax({
            url: "./ajax/checknew.php",
            data: {timestamp: timee},
            success: function(data) {
                $("#chMsgCont").append(data);
                if(data != null) {
                var div = $('#chMsgCont');
                var o = div.offset().top; 
                div.scrollTop( o + 12302012 );
                }
            }
        });
    },1000);

Even if data is null, $("#chMsgCont) scrolls down, why?

Answer 1

Try it this way:

if(data)

Or this way:

if(data != null && data != "")

Basically, if(data) is considered as data is false in these cases:

• data is “” or ” => empty string

• data is false

• data is null

• data is undefined