var exec = false;  
function onceOnly(thform) { 
	if(exec == true){ return false; }; 
	exec = true; 
	obj = thform.getElementsByTagName('input'); 
	for (i=0; i < obj.length; i++) { 
		if((obj[i].type) == 'submit' || (obj[i].type) == 'image' || (obj[i].type) == 'reset') { 
			obj[i].disabled = true; 
		}; 
	}; 
	//alert('mukou'); 
	return true; 
};