function view_sub_menu(cat){
        	clear_sub_menu();
			window.document.getElementById(cat + '_subcats').className='sub_categories';
	}
	function clear_sub_menu(){
    		                     				window.document.getElementById('T-Shirts_subcats').className='invisible';
           		                    				window.document.getElementById('Womens_subcats').className='invisible';
           		                    				window.document.getElementById('Sweatshirts_subcats').className='invisible';
           		                    				window.document.getElementById('Business_subcats').className='invisible';
           		                    				window.document.getElementById('Athleticwear_subcats').className='invisible';
           		                    			                    			                    			                    			                    			                    			                    				}