jquery javascript sorting

I am currently trying to build jquery filtering. Here is my part of my keyword filtering javascript code:

This is the problem:

<div class="task" data-task="#<Task:0x007fe319f71490>">
                  <ul>
                    <li>
                      <input name="task[5]" type="hidden" value="0"><input class="checkbox-task" type="checkbox" value="1" name="task[5]" id="task_5">
                      <label for="Some_Task0">Some task0</label>
                      <br>
                      <label for="Description">Description</label>
                      Finish this assessment.
                      <br>
                      <label for="Due_Date">Due date</label>
                      2015-06-22
                      <br>
                      <a class="btn btn-warning" href="/tasks/5/edit">Update Task</a>
                    </li>
                  </ul>
                </div>

The terms that are relevant to me are: 1) Some_Task0 2) Finish this assessment.

How can I obtain those words?

I currently am doing this:

$(task).find("label")

How to I specifically get those labels so I can get those values so I can then run a RegExp.test on the letter that I type into the search bar?