Plain text output problem with Mozilla

I am using the javascript function below to get plain text in an FCK editor before submitting it to database. <br> in HTML is being converted to line break smoothly in Interner Explorer, but not in Mozilla. Instead it create while characters. What is the best way to make it work?

function getText(editorName)
{
// This functions shows that you can interact directly with the editor area
// DOM. In this way you have the freedom to do anything you want with it.

// Get the editor instance that we want to interact with.
var oEditor = FCKeditorAPI.GetInstance(editorName) ;

// Get the Editor Area DOM (Document object).
var oDOM = oEditor.EditorDocument ;

var iLength ;

// The are two diffent ways to get the text (without HTML markups).
// It is browser specific.

if ( document.all ) // If Internet Explorer.
{
iLength = oDOM.body.innerText ;
}
else // If Gecko.
{
var r = oDOM.createRange() ;
r.selectNodeContents( oDOM.body ) ;
iLength = r.toString() ;
}