function selectbox(num) { 
	 var f = new getObj('tdropdown_'+num); 
	 if (f.style.display == 'none'){ 
		 f.style.display = ''; 
	 } 
	 else { 
		 f.style.display = 'none'; 
	 } 
 } 

function getObj(name) { 
	 if (document.getElementById) { 
		 this.obj = document.getElementById(name); 
		 this.style = document.getElementById(name).style; 
	 } 
	 else if (document.all) { 
		 this.obj = document.all[name]; 
		 this.style = document.all[name].style; 
	 } 
	 else if (document.layers) { 
		 this.obj = document.layers[name]; 
		 this.style = document.layers[name]; 
	 } 
 }