var is_login_click = 0;

function login_form()
{
	if ( is_login_click == 0 )
	{
		document.getElementById("login_form").style.display = "block";
		is_login_click = 1;
	}
	else
	{
		document.getElementById("login_form").style.display = "none";
		is_login_click = 0;	
	}
}