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Remove class from all and add to one clicked

I am writing a function where I want to remove an active class from all elements and add it to the one which was just clicked. Problem is that when I click the element all of them get the active class. Please see the code below.
var pagination = $('.pagination div');
function pager() {
pagination.removeClass('active', function(){
$(this).addClass('active');
});
}
$('.pagination div').on("click", function (){
pager();
});
I could use the code below, which works actually, but the reason I want to use the above one is to have possibility adding other functions in it which will be called later on click.
$('.pagination div').on('click',function(){
$('.pagination div').removeClass('active');
$(this).addClass('active');
});
HTML if needed
<div class="pagination">
<div class="pagination1"></div>
<div class="pagination2"></div>
<div class="pagination3"></div>
<div class="pagination4"></div>
</div>

By using a separate function, you are losing your reference to the current object (this). You will need to use a parameter to get your way working.
function pager(element) {
pagination.removeClass('active', function(){
element.addClass('active');
});
}
$('.pagination div').on("click", function (){
pager($(this));
});

I want to use the above one is to have possibility adding other
functions in it which will be called later
Try this:
function pager(el) {
pagination.removeClass('active', function(){
$(el).addClass('active');
});
}
$('.pagination div').on("click", function (){
pager(this);
});

$('div.pagination').on('click', 'div', function(){
$(this).addClass('active').siblings().removeClass('active');
});

How about this:
var pagination = $('.pagination div');
function pager(selector) {
$('.pagination div').removeClass('active');
$(selector).addClass('active');
}
$('.pagination div').on("click", function (){
pager(this);
});

var pagination = $('.pagination div');
function pager(that) {
pagination.removeClass('active', function(){
that.addClass('active');
});
}
$('.pagination div').on("click", function (){
pager($(this));
});

Editable JSFiddle
HTML
<div class="pagination">
<div class="pagination1">Pagination 1</div>
<div class="pagination2">Pagination 2</div>
<div class="pagination3">Pagination 3</div>
<div class="pagination4">Pagination 4</div>
JavaScript
$(function() { // DOM loaded event handler
function pager (element) {
$(".pagination div").removeClass("active");
element.addClass("active");
}
$(".pagination div").click(function() {
var element = $(this);
pager(element);
});
});
CSS
.active {
color : red;
}
I used your function in 2 steps :
First, I remove all active class by using $(".pagination div").removeClass("active"); which actually apply this effect on all sub div
then, I use the element passed through parameter to the function to scope it, and be able to add the proper class

Use id for all the element then add active class to each element which has been click or use e.target this will track the current element
$('.pagination').click(function(e){
$('.pagination').removeClass('active');
$(e.target).addClass('active');
});

Display read more button

I want to use a read more button after a text is larger than 300 characters.
I use this jQuery to fix this, but it is not working as I want.
var $j = jQuery.noConflict();
$j('.reviewtekst').each(function() {
var $pTag = $j(this).find('p');
if($pTag.text().length > 300){
var shortText = $pTag.text();
shortText = shortText.substring(0, 300);
$pTag.addClass('fullArticle').hide();
$pTag.append('<a class="read-less-link">Lees minder</a>');
$j(this).append('<p class="preview">'+shortText+'</p><div class="curtain-shadow"></div><a class="read-more-link">Read more</a>');
}
});
$j(document).on('click', '.read-more-link', function () {
$j(this).parent().hide().prev().show();
});
$j(document).on('click', '.read-less-link', function () {
$j(this).parent().hide().next().show();
});
See this JSFiddle: https://jsfiddle.net/8cm67cun/1/
How can I make this work, to display the <a> class outside the <p> class.

Here is updated version https://jsfiddle.net/8cm67cun/2/ now it works fine with a tag outside the p
$j(document).on('click', '.read-more-link', function () {
$j(this).hide().parent().find('.preview').hide().prev().show();
});
$j(document).on('click', '.read-less-link', function () {
$j(this).parent().hide().next().show();
$j(this).parents('.reviewtekst').find('.read-more-link').show();
});

.addClass to element adds a styling then removes, how do I fix

I have a code
var prev;
function addClass( classname, element ) {
prev = cn;
var cn = document.getElementById(element);
$(cn).addClass("selected");
}
The element in the dom look like this:
<div class="arrowgreen">
<ul>
<li>Manager</li>
<li>Planner</li>
<li>Administrator</li>
</ul>
</div>
For 'arrowgreen' I have a styling which changes the li styling on rollover and click.
When an element is clicked on, I want to apply the 'selected' classname to the element.
It does this for a split second and then reverts back.
The css looks like
.arrowgreen li a.selected{
color: #26370A;
background-position: 100% -64px;
}

Working jsFiddle Demo
In usage of $ in your code, I see that you are using jQuery.
There is no need to set onclick internally.
Let's jQuery handle it for you:
// wait for dom ready
$(function () {
// when user clicks on elements
$('.arrowgreen li a').on('click', function (e) {
// prevent default the behaviour of link
e.preventDefault();
// remove old `selected` classes from elements
$('.arrowgreen li a').removeClass('selected');
// add class `selected` to current element
$(this).addClass('selected');
});
});

Working JSFiddle
There was an error in your HTML, a " that opened a new string after onclick.
var prev;
function addClass(classname, element) {
var cn = document.getElementById(element);
prev = cn; //does nothing useful really
$(cn).addClass("selected");
}
<div class="arrowgreen">
<ul>
<li>Manager
</li>
<li>Planner
</li>
<li>Administrator
</li>
</ul>
</div>
Remember to include jQuery in your page!
There is a way to do this without jQuery anyway:
function addClass(classname, element) {
var cn = document.getElementById(element);
prev = cn; //does nothing useful really
cn.className += " " + classname;
}

Similar way to do it:
(function ($) {
$('.arrowgreen > ul > li > a').on('click', function (e) {
e.preventDefault();
$(this).addClass('selected').siblings().removeClass('selected');
});
}(jQuery));

How to convert javascript inline code to jQuery?

I have this working jQuery + inline javascript which causes a conflict with existing jQuery.
<script>
var jq=jQuery.noConflict();
function goto(id, t){
jq(".contentbox-wrapper").animate({"left": -(jq(id).position().left)}, 600);
jq('#slide a').removeClass('active');
jq(t).addClass('active');
}
</script>
&lta class="active" href="#" onClick="goto('#kr', this); return false">
&lta class="active" href="#" onClick="goto('#en', this); return false">
(I've tried to resolve the conflict as you can see but I believe the conflict arises from the inline javascript.)
How can I convert this inline javascript? Thanks.

You can bind it like:
<script>
//var jq=jQuery.noConflict();
function goto1(id, t){
...
return false; // return false to prevent the link's default action
}
// means once your DOM is ready, and a.active is available to be bound
$(document).ready(function() {
// bind all clicks on a.active to the function 'goto1'
$('a.active').click(goto1);
});
</script>
Variable names like goto can be potential causes of confusion later on. Changed it above to goto1.

Inline JS (embed into HTML) is hardly maintainable, I'd suggest:
HTML:
<div id="parent"> <!-- or any other parent el. -->
Anchor
</div>
jQuery:
(function($){ // remap $ to jQuery
$(function(){ // DOM ready
$('#parent').on('click', 'a', function( ev ){
ev.preventDefault();
var krPos = $('#kr').position().left;
$(".contentbox-wrapper").animate({"left": -krPos }, 600);
$('#slide a').removeClass('active');
$(this).addClass('active');
});
});
})(jQuery);

$('.active').on('click', function() {
var $this = $(this);
var id = $this.attr('href');
$(".contentbox-wrapper").animate({"left": -($(id).position().left)}, 600);
$('#slide a').removeClass('active');
$this.addClass('active');
return false;
});
huangism answered it for me.
https://stackoverflow.com/users/1058134/huangism

returning clicked li class in an ul javascript/jquery

My code (the html page):
<nav>
<ul>
<li id="homeLink">Home</li>
<li id="rekenLink">Rekenmachine</li>
<li id="bakkerLink">Parkeergarage</li>
<li id="garageLink">Bij de bakker</li>
<ul>
</nav>
The javascript/jquery behind it:
$(function () {
$("ul").click(function () {
// here I want to get the clicked id of the li (e.g. bakkerLink)
});
});
How do I do that?

Use the .on() method with signature $(common_parent).on(event_name, filter_selector, event_listener).
Demo: http://jsfiddle.net/gLhbA/
$(function() {
$("ul").on("click", "li", function() {
// here I want to get the clicked id of the li (e.g. bakkerLink)
var id = this.id;
alert(id);
});
});
Another method is to bind the event to li instead of ul:
$(function() {
$("li").click(function() {
// here I want to get the clicked id of the li (e.g. bakkerLink)
var id = this.id;
alert(id);
});
});

Use jQuery on() instead of click and pass li as selector.
$(function() {
$("ul").on('click', 'li', function() {
//Here this will point to the li element being clicked
alert(this.id);
});
});
on() reference - http://api.jquery.com/on/

$(function() {
$("li").click(function() {
alert(this.id);
});
});
edit: jsfiddle link

Handle the click event of the <li> instead of the <ul>.
You can then get this.id.

Use the event's target (The anchor that was clicked) and then grab its parent's id:
$(function() {
$("ul").click(function(e) {
alert(e.target.parentNode.id);
});
});
JSFiddle

here is one of the way to do. Make sure your using the latest jquery file.
$("ul li").on('click', function() {
console.log($(this).attr("id"));
});

You may try
$(function () {
$("li").click(function () {
var id = $(this).attr("id");
alert(id);
});
});
or
$(document).ready( function() {
$("li").click(function () {
var id = $(this).attr("id");
alert(id);
});
});