Question

I wrote a code that whould change a li’s class to active and show the correct content on click but I also would like to be able to link a visitor to example: http://www.socal.nu/index.php#tab2 to activate tab2.

Code:

$(document).ready(function() {

//Default Action
$(".tab_content").hide();
$("ul.tabs li:first").addClass("active").show();
$(".tab_content:first").show();

//On Click Event
$("ul.tabs li").click(function() {
$("ul.tabs li").removeClass("active");
$(this).addClass("active");
$(".tab_content").hide();
var activeTab = $(this).find("a").attr("href");
$(activeTab).fadeIn();
return false;
});

});

Edited to include the (x)html structure of the tabs list (as posted by the OP in a comment to @slightlymore’s answer):

<ul class="tabs">
  <li><a href="#tab1">Hem</a></li>
  <li><a href="#tab2">Projekt</a></li>
  <li><a href="#tab3">Om SOCAL</a></li>
  <li><a href="#tab4">Kontakt</a></li>
</ul>

Answer 1

To get the tab from the URL, do this:

var tab = window.location.hash;

Then you could trigger the click event for the li that has the a with the proper href:

var tab = window.location.hash;

    // Fire click on the <li> that has the <a> with the proper 'href' attribute
$("ul.tabs li:has(a[href=" + tab + "])").click();

Or you could reuse the function you created for the click event, and the initial page load.

  // Function that is used for click event and page load
function loadTab() {
    $("ul.tabs li").removeClass("active");
    $(this).addClass("active");
    $(".tab_content").hide();
    var activeTab = $(this).find("a").attr("href");
    $(activeTab).fadeIn();
    return false;
}

  // set up Click Event
$("ul.tabs li").click( loadTab );

var tab = window.location.hash;

  // check to see if there was a tab in the location, and if
  //    so, call loadTab if from the context of the proper <li>.
if( $("ul.tabs li:has(a[href=" + tab + "])").length ) {
    loadTab.call($("ul.tabs li:has(a[href=" + tab + "])")[0]);
}