jquery - keep window from changing scroll position while prepending items to a list?

Question

I have a page that displays messages and I want it to work just like Facebook, but without the lazy loader. Messages are displayed in chronological order, most recent last.<

Answer 1

No need for jQuery here, just check for changes in the elements scrollHeight and adjust the scrollTop accordingly, ie:

var lastScrollHeight = el.scrollHeight;
for(var n=0; n<10; n++){
    // Prepend here...
}
var scrollDiff = el.scrollHeight - lastScrollHeight;
el.scrollTop += scrollDiff;

Demo

http://jsfiddle.net/fkqqv28e/

jQuery

To access the native DOM node from a jQuery collection, use array access; ie:

var lastScrollHeight = $('#myElement')[0].scrollHeight;
for(var n=0; n<10; n++){
    $('#myElement').prepend('
prepended '+Math.random()+'
');
}
var scrollDiff = $('#myElement')[0].scrollHeight - lastScrollHeight;
$('#myElement')[0].scrollTop += scrollDiff;