#define html_hiddenvar(x) do {if (x && *x) html_input_hidden(#x , quotequotes(x));} while (0)
#define html_hiddenivar(x) do {if (x) html_input_hidden(#x, xistr((int)x)); } while (0)
#define html_input_hiddenivar(x) do {char *p = cgi_variable(#x); if (p && *p) x = atoi(p);} while (0)
#define html_url_var(p, x, v) (v && *v ? sprintf(p, "%s=%s;", x, v) : 0)
#define html_url_ivar(p, x) (x? sprintf(p, #x ## "=%d;", x) : 0)