Develop Reference

Adding class to menu item in Wordpress

I have menu with items. I want to add to tag class with name "name". I try to use:
var element = document.getElementById('myElement');
element.classList.add('myClass');
But the tag doesn't have any ID or class.
It's even possible with Javascript?
<ul id="menu-main">
<li id="menu-item">
ODKAZ
</li>
</ul>

If you really want to add the class with javascript, you can do:
var element = document.getElementById('menu-item');
element.getElementsByTagName("a")[0].classList.add('js-target-scroll');
<ul id="menu-main">
<li id="menu-item">
ODKAZ
</li>
</ul>
But beware that the "onemenu" you are talking about is looking for this css-class and if your own script is not run before that, this won't work since the class is not yet added.
If it's your own theme you are developing, you can add the css-class server side with custom walker.

If you want to add the class for all menu item anchor tags, you can use the code below. If not, use what Esko has suggested in his answer and comments.
var menuItemLinks = document.querySelectorAll("#menu-main li a");
menuItemLinks.forEach(function(element) {
element.classList.add("myClass");
});
<ul id="menu-main">
<li>Item 1</li>
<li>Item 2</li>
<li>Item 3</li>
<li>Item 4</li>
</ul>

highlight current menu item with jquery

I need to higlight current category. I can do it like that, no problem:
javascript
var url = document.URL;
$('.nav a[href="'+url+'"]').addClass('active');
html
<div class="nav">
<ul>
<li>Category 1</li>
<li>Category 2</li>
</ul>
</div>
but i dont want to link to http://wholewebadress.com/catphp?cat.php?id=1 in html codes, instead i want to link to cat.php?id=1. So i want my html codes look like below;
<div class="nav">
<ul>
<li>Category 1</li>
<li>Category 2</li>
</ul>
</div>
Looks like, i need to edit my javascript code. Any ideas how to do that?

The following adds the active class to any link that contains id=1 in the URL:
$('.nav a[href*="id=1"]').addClass('active');
You can change the matching part ("id=1") to select whatever URL criteria you need.

Use var url = location.pathname + location.search;
W3Schools information
Edit: since it seems to need to parse for the ending:
var ending = url.slice(url.lastIndexOf('/'));

Counting Sub-Menu Items jQuery without CSS Classes

The great Google and SO didn't render search results regarding this. Some were similar but didn't quite get me there.
I am in need of making a classless submenu that will attach a style attribute to each individual <li> in the sub <ul> in order to set a min-width property based on the number of sub list items.
The HTML
<nav>
<ul>
<li>HOME</li>
<li>ABOUT COMPANY</li>
<li>
ABOUT PRODUCT
<ul>
<li>Item 1</li>
<li>Item 2</li>
</ul>
</li>
<li>GETTING STARTED</li>
<li>
PATIENT SUPPORT
<ul>
<li>Item 1</li>
<li>Item 2</li>
<li>Item 3</li>
</ul>
</li>
<li>CONTACT</li>
<li>eUPDATES</li>
</ul>
</nav>
The JavaScript
$('.sub').text(function() {
var count = $(this).next().find('li').length;
var totalwidth = count * 115;
$(this).next().find('li').parent('ul').attr('style','min-width:'+totalwidth+'px');
});
I need to be able to do this without searching based off the class "sub". I've tried a few times, but none of it seems as powerful as the code I'm currently using. The backend developer I'm working with is requiring it to all be simple <ul><li></li></ul> structure with no classes.
If anyone can help point me in the right direction on this, I'd greatly appreciate your time and help!

Target all LI items that contain UL's, find the number of LI's in those UL's, and multiply for width :
$('ul', 'li').css('min-width', function() {
return ( $(this).find('li').length * 115 ) + 'px';
});

Adding auto increment value to li element

im a css/designer guy so please excuse my lameness in not knowing any .js
basically i want to know how to add an auto incremental id to a list item with javascript / jquery for something that i am trying to add some css to.
before
<li id="">Item number 1</li>
<li id="">Item number 2</li>
<li id="">Item number 3</li>
after
<li id="1">Item number 1</li>
<li id="2">Item number 2</li>
<li id="3">Item number 3</li>
thanks in advance and especially just for reading this
tried all the responses, nothing has worked on a plain html page with nothing but the ul/li items.
thanks to all that tried, i have failed in a big way.....im not a coder

I'm going to give your li tags an encompassing ul with an id in case there are other li tags on the page that you don't want to order, but in jQuery this is pretty easy for:
<ul id="ordered">
<li>Item number 1</li>
<li>Item number 2</li>
<li>Item number 3</li>
</ul>
You would simply use the each method:
$('#ordered li').each(function(i,el){
el.id = i+1;
});
I would recommend using something other than just a plain integer for an id though, so maybe something like 'ordered' + (i+1) instead of just i+1 above.

Your tags say jQuery, so:
$("li").each(function(i){this.id = i})
So you can learn: you make a collection of HTML nodes with the $('foo') syntax. You use CSS selectors, so li will get -every- <li> on the page.
.each loops over those collected HTML elements, and does something to them. The 'something' is in the code function(i){this.id = i}. jQuery passes which loop you're on to the function as i, and the code inside the curly braces sets the id of that particular element to i.

If you need id's for styling, that's a bad idea. What you should do is use css 3 pseudo class :nth-child(n) which is in your area of css.

I'm going to wrap your code in a div so it's easier to code for
<div id="increment">
<li>Item number 1</li>
<li>Item number 2</li>
<li>Item number 3</li>
</div>
And js would be:
function loadcode(){
var increments = document.getElementById("increment");
var li = increments.getElementsByTagName("li");
for (i=0;i<li.length;i++) li[i].setAttribute("id", i+1);
}
and in your HTML:
<body onload="loadcode()">

How to Insert an incremental variable with Javascript/Jquery?

This, I'm sure is a pretty basic question about JavaScript, so apologies in advance.
I have simple unordered list:
<ul>
<li>Item number 1</li>
<li>Item number 2</li>
<li>Item number 3</li>
<li>Item number 4</li>
<li>Item number 5</li>
</ul>
How would I be able to prepend an incremental number to those 5 items,
so I get:
<ul>
<li><span>1</span>Item number 1</li>
<li><span>2</span>Item number 2</li>
<li><span>3</span>Item number 3</li>
<li><span>4</span>Item number 4</li>
<li><span>5</span>Item number 5</li>
</ul>
The logic behind the increment variable is getting me.

You can iterate over the elements using $.each, using the index argument on the callback function, then build the span element using the current element, and we prepend it to the li:
$('ul li').each(function (i) {
$('<span>'+ (i+1) +'</span>').prependTo(this);
// or $('<span></span>').html(i+1).prependTo(this);
});
Check the above snippet here.
Note that I'm adding one to the index i+1, that's because the indexes are zero-based, also I wrap the addition between parentheses because it is in the middle of a string concatenation.

In steps it'd look like this:
You take all LI items and iterate through all of them by adding span with (lis[index]+1)
Next time you insert a LI element you insert it with span who's text is lis.length+1.