SO jQuery Fiddle

Test Fiddle mainly for SO Questions jQuery 1.4.3, UI 1.8.5

by Nick Craver

HTML

<link rel="stylesheet" href="http://ajax.googleapis.com/ajax/libs/jqueryui/1.8.5/themes/ui-lightness/jquery-ui.css">
<div class = "current_parent level-0">
  <a> Parent Link </a>
  <ul class= "children">
     <li class = "level-1">
           <a href="#test"> Link to child </a>
     </li>

     <li class = "level-1">
          <a href="#test"> Link to child </a>
     </li>

     <li class = "level-1 current_page_item">
           <a href="#test"> Link to child </a>
     </li>

     </ul>
</div>

JavaScript

//Get URLs, run a length check against them. Execute functions are necessary. Pass the functions the relevant URL
        var nextURL= $(".current_page_item").next().find("a").attr("href"); //Get the HREF of the next page in list
        var previousURL= $(".current_page_item").prev().find("a").attr("href"); //Get the HREF of the previous page in list


        if(previousURL === undefined){
            alert ("Hiding prev URL!");
            $('.previous_link').hide();
        }else if(previousURL.length >= 1){    
            alert ("Setting prev URL!");
            setPrevPageLink(previousURL);
        }

        if(nextURL === undefined){
            alert ("Hiding Next URL!");
            $('.next_link > a').hide();
        }
        else if (nextURL.length >= 1){
            alert ("Setting next URL!");
            setNextPageLink(nextURL);
        }

       function setPrevPageLink(previousURL) {

           var prevTitle = $(".current_page_item").prev().find("a").attr("title"); //Get the title of previous page in list. WP provides.
           $(".previous_link > a").attr("href", previousURL); //Set the 'Previous Link' to the URL of the previous item in list.
           $(".previous_link > a").text(prevTitle); // Set the Title Text of the Link to the title of the previous Item in the List
           alert ("Previous URL is" + previousURL + "and it's title is " + prevTitle + "and it's length is " + previousURL.length); //Drop an alert for Debug
       }

       function setNextPageLink(nextURL){

            var nextTitle = $(".current_page_item").next().find("a").attr("title");
            $(".next_link > a").attr("href", nextURL);
            $(".next_link > a").text(nextTitle);
            alert ("Next URL is" + nextURL + "and the title is" + nextTitle + "and it's length is" + nextURL.length);
       }