docs: function _fnConvertToWidth ( sWidth, nParent )
  		{
  			if ( !sWidth || sWidth === null || sWidth === '' )
  			{
  				return 0;
  			}
  			
  			if ( !nParent )
  			{
  				nParent = document.getElementsByTagName('body')[0];
  			}
  			
  			var iWidth;
  			var nTmp = document.createElement( "div" );
  			nTmp.style.width = _fnStringToCss( sWidth );
  			
  			nParent.appendChild( nTmp );
  			iWidth = nTmp.offsetWidth;
  			nParent.removeChild( nTmp );
  			
  			return ( iWidth );
  		}