var main_size = null;

function watermerkInit()
{
	var el_kolom_3  = document.getElementById('kolom_3');
	if(el_kolom_3 != null)
	{
		var el_main	  	= document.getElementById('main');
		var main_height = null;
		
		if(main_size == null)
		{
			main_height = el_main.offsetHeight;
			main_size	= main_height;
		}
		else
		{
			main_height = main_size;
		}	
		
		main_height = main_height - 10;
			
		el_kolom_3.style.height = main_height+'px';
	}
}