jQuery Click on next element - jquery-selectors

Question

I have a problem with programming jQuery and I hope that you can help me even if a speak english like an alien %).
I'm doing a site with horizontal scrolling, you can see it here http://www.kinetics.ru/index_kin.html
I have a menu at the left and two buttons PREV and NEXT at the bottom.
Menu is working correctly, but I need to let the bottom buttons work.
By clicking for example on NEXT I need that code made a click on next menu btn after the one that have style 'on'.
The code is:
<div class="menu">
<ul class="nav">
<li id="main"><img src="img/menu/about.png" /></li>
<li><img src="img/menu/uslugi.png"/></li>
<li><img src="img/menu/portfolio.png"/></li>
<li><img src="img/menu/clients.png"/></li>
<li><img src="img/menu/contacts.png"/></li>
</ul>
</div>
...
<div class="bottomNav" style="position: absolute; z-index: 11">
<div style="height: 26px; width:98px; margin:-75px 0 0 500px; position: fixed" class="back"><img src="img/back.png"</div>
<div style="height: 26px; width:114px; margin:-25px 0 0 600px; position: fixed" id="next"><img src="img/forward.png"</div>
And my not working jQuery code for next btn:
$('bottomNav, #next img').click(function(){
if ($('ul.nav').find('img').hasClass('on')){
$('ul.nav').next().click();
}
});
Also I've tried to do like this:
$('bottomNav, #next img').click(function(){
$('ul.nav img').click(function(){
if ($(this).hasClass('on')){
$(this).next().click();}
});
});
P.S. Sorry for my noobish question. I just got a task at work to make a site and nobody cares that a designer is NOT the same as web-designer. I have no possibility to learn first, I have to learn and do at same time.

Answer 1

You have to review jQuery selectors and as well your HTML code, it's terribly wrong. Firebug says:
I modified your code in proper way:
<div class="bottomNav" style="position: absolute; z-index: 11">
<div id="prev" style="height: 26px; width:98px; margin:-75px 0 0 500px; position: fixed">
<img src="img/back.png" />
</div>
<div id="next" style="height: 26px; width:114px; margin:-25px 0 0 600px; position: fixed" >
<img src="img/forward.png" />
</div>
</div>
JavaScript (It's pretty simple and I didn't test it, but it should give you an idea).
$('#prev').click(function () {
var $activeLi = getActiveLi();
var $prevLi = $parentLi.prev();
if ($prevLi.length > 0) {
$prevLi.find('a').click();
}
});
$('#next').click(function () {
var $activeLi = getActiveLi();
var $nextLi = $parentLi.next();
if ($nextLi.length > 0) {
$nextLi.find('a').click();
}
});
function getActiveLi() {
var $activeImg = $('.menu .nav img.on');
var $activeLi = $activeImg.closest('li');
return $activeLi;
};
But beeing seriously: before continuing developing your web site you seriously should put some effort in learnin hot to use jQuery and how to structure HTML...

Answer 2

Solved!
Thank you again!
Your code was really helpfull.
I have modified it a little bit for my needs and also changed in line
var $activeLi = $activeImg.closest('li');
closest('li') to parents('li'), cause it wasn't working like that.
So now code looks like this:
$('#prev').click(function () {
var $prevLi = getActiveLi().prev();
if ($prevLi.length > 0){$prevLi.find('img').click();}
});
$('#next').click(function () {
var $nextLi = getActiveLi().next();
if ($nextLi.length > 0){$nextLi.find('img').click();}
});
function getActiveLi() {
var $activeImg = $('.menu .nav img.on');
var $activeLi = $activeImg.parents('li');
return $activeLi;
};
Also i guess, that i have understood why firebug was showing so big disaster in code... i have forgot to close the tag :)))
Anyway...MANY THANKS TO YOU!
P.S. third day reading a giant book about jQuery :)