Show Hide using display.style in javascript problem in Firefox

An already javascript function was used to show/hide an array of elments in an HTML page.
It worked perfectly in IE but in Firefox it gave a problem when we used to show/hide multiple times on an element. A new row/column was added in every iteration of show hide.

On investigation, a single line code change made in work fine in both IE and firefox

Old Code

function showHideElement(elementId, showHideFlag) {
var elementObj = document.getElementById(elementId);
if(showHideFlag == 1) {
elementObj.style.display = 'block';
} else if(showHideFlag == 0) {
elementObj.style.display = 'none';
}
}

New Code

function showHideElement(elementId, showHideFlag) {
var elementObj = document.getElementById(elementId);
if(showHideFlag == 1) {
elementObj.style.display = '';
} else if(showHideFlag == 0) {
elementObj.style.display = 'none';
}
}

A single line change from elementObj.style.display = 'block' to elementObj.style.display = '' stopped creation of blank rows/columns on every iteration of show hide

http://www.ozzu.com/ftopic41924.html
http://www.velocityreviews.com/forums/t160487-firefox-and-stylequotdisplayblockquot-on-table-row.html