How to write this simple javascript or jquery?

Question

I have some navigation links, for example:

<ul id="nav">
   <li><a href="index.html">Home</a>
   <li><a href="about.html">About</a>
   <li><a href="contact.html">Contact</a>
</ul>

How do I add a CSS class with a name activeto the opening tag <li>of a list item that contains a a hrefvalue that matches the current URL?

For example, if the current page the user is on is located about.html, then the navigator should look like this:

<ul id="nav">
   <li><a href="index.html">Home</a>
   <li class="active"><a href="about.html">About</a>
   <li><a href="contact.html">Contact</a>
</ul>

Note:

URLs can have additional parameters, for example:

about.html = Foo bar &? Bar = Loo

therefore, everything that is used to detect url should not take parameters into account, but simply the name of the page and extension.

I would prefer to achieve this in plain JavaScipt, since I am not using jQuery for anything else on the site, but that's fine.

Edit

index.html URL-, , , :

http://www.sitename.com/

, , home list.

Answer 1

JQuery

if(window.location.pathname === '') {
     $('#nav li:first-child').addClass('active');
}
else {
    var path = window.location.pathname;
    path = path.substr(path.lastIndexOf('/') + 1);
    $('#nav li').filter(function(index) {            
        return path === $(this).children('a').attr('href');
    }).addClass('active');
}

JavaScript:

var menu_elements = document.getElementById('nav').children;
if(window.location.pathname === '') {
     menu_elements[0].className += ' active';
}
else {
    var path = window.location.pathname;
    path = path.substr(path.lastIndexOf('/') + 1);
    for(var i = menu_elements.length; i--;) {
        var element = menu_elements[i];
        var a = element.children[0];
        if(a.href === path) {
            element.className += ' active';
            break;
        }
    }
}

: children[] FF 3.0. children, getElementsByTagName.

Answer 2

window.onload=function() {
  var activeLi;
  if (location.pathname) { 
    var fileName = location.pathname.substring(pathname.lastIndexof('/')+1);
  /* just take the start - 
     not handling filenames that are substrings of other filenames 
     nor filenames with more than one dot. */
    fileName = fileName.split('.')[0]; 
    var links = document.getElementById('nav').getElementsByTagName('a');
    for (var i=0;i<links.length;i++) {
      if (links[i].href.indexOf(fileName)==0) { // starts with filename
        activeLi = links[i].parentNode;
        break; 
      }
    }
  }
  else { // no page given
    activeLi = document.getElementById('nav').getElementsByTagName('li')[0];
  }
  if (activeLi) activeLi.className="active";
}

ADD Name, LI, , jQuery, .

Answer 3

//Get sub-domain url 
var currentUrl = window.location.href,
    splitUrlArr = currentUrl.replace(/\?.*/,'').split('\/');
    subDomainUrl = splitUrlArr[splitUrlArr.length-1];
//if url matches the site home url, add classname 'active' to first li
if(splitUrlArr.join('\/') == currentUrl) {
    document.getElementById('nav').getElementsByTagName('li')[0].className = "active";
}else {
    //Find the matching href and add className 'active' to its parent li
    var targetLi = null;
    var links = document.getElementById('nav').getElementsByTagName('a');
    for (var i=0; i < links.length; i++) {
        if (links[i].href === subDomainUrl) { 
            targetLi = links[i].parentNode;
            break; 
        }
    }
    if(targetLi) { targetLi.className = "active"; }
}