Internet Explorer provides an innerText property to get or set the text between the start and end tags of the object. Firefox does not provide an innerText property but a textContent property to get or set the inner text. For the browsers that do not provide a property to get or set the inner text, you can clear the HTML tags inside the innerHTML property.

function GetInnerText(elem) {

   return (typeof(elem.innerText) != 'undefined') ? elem.innerText :

          (typeof(elem.textContent) != 'undefined') ?   elem.textContent : elem.innerHTML.replace(/<[^>]+>/g, '');