Question

I have two questions:
1. How can I make my table rows clickable and still load ajax content in the div ajaxContent?
2. How can I add a loading-animation in the <div id='ajaxContent'>

this is students.php

<?php

echo "<table id='tblStudents'>\n";

        echo "<thead><tr>\n";
            echo "<td>Namn</td>\n";
            echo "<td>Personnummer</td>\n";
            echo "<td>Startdatum</td>\n";
            echo "<td>Slutdatum</td>\n";
        echo "</tr></thead>\n";

        echo "<tbody>\n";
        while ($row = mysql_fetch_assoc($list_students)) {

            $count = ($count + 1) % 2; //will generate 0 or 1 and is used to alternatve the css classes row0 and row1 in the loop result

            echo "<tr class='row$count'>\n";
                echo "<td><a class='ajaxCall' href='#' rel='".$row['student_id']."'>" . $row['student_firstname'] . "</a> " . $row['student_lastname'] . "</td>\n";
                echo "<td>" . $row['student_socialnr'] . "</td>\n";
                echo "<td>" . $row['student_startdate'] . "</td>\n";
                echo "<td>" . $row['student_enddate'] . "</td>\n";


            echo "</tr>\n";
        }
        echo "</table>\n";  
}

?>
<div id='ajaxContent'></div>

<script src="js/jfunc.js"></script>

This is jfunc.js

$('a.ajaxCall').click(function() {
var rowId = $(this).attr('rel');

 $.ajax({
  type: "get",
  url: '/page/editstudent.php',
  data: { student_id: rowId },
  success: function(data) {
  $('#ajaxContent').html(data);
 }
}); 
});

Answer 1

Use event-delegation and listen for all clicks on the table.

$("#tblStudents").on("click", "tr", function(e){
    var row_id = $("td:first a.ajaxCall", this).attr("rel");
    $("#ajaxContent").html("Loading...");
    $.ajax({
        url: "/page/editstudent.php",
        data: { 'student_id':row_id },
        success: function(data){
            $("#ajaxContent").html(data);
        }
    });
});

Side-issues

You don’t need to add a classname of 0 or 1 to each table-row. With pure CSS you can target even and odd rows to style them differently:

#tblStudents tr:nth-child(even) {
    background: #f1f1f1;
    color: #999;
}

Additionally, I would encourage you to store the student id on a data attribute instead of the rel attribute. This is what the data attributes exist for. You could even store them on the <tr> itself. More about those at http://api.jquery.com/data/#data-html5.