I cannot append a child element to a list

I used to be able to append a child to a list dynamical but now for some reason the JavaScript functions stop working. Also the error console does not throw any errors and I have place several alert('') methods in between the code to make sure that the method is actually running. this is what I used to have and it used to work perfectly fine:

var o = document.getElementById('searchResults');

var li = document.createElement('li'); //creates a list item tag

//if counter is even then highlight the cell different than an odd one
if ((counter) % 2开发者_如何学Go == 0) {
    li.setAttribute('class', 'par');
} else {
    li.setAttribute('class', 'non');
}

// I copied the inner html from a row that was displaying. I got rid of the dynamic variables
// just so it is a little easier to understand.
li.innerHTML = "<label class='list3p1'>testing</label><label class='list3p2'>testing2</label><label class='list3p3'>2:23</label>";
o.appendChild(li);

this function was working but as I added other tables to index.php this functions stopped working. Moreover I have used this similar method in other pages. Also other methods are working and that is the only function that does not seem to work.

It had to do with the visibility. It took me a long time to find. I had the id of the table repeated and the visibility of the other table was hidden therefore I was adding items to a hidden table. sorry for the fool question.