function checkNumber()
{
var number = document.getElementById('number').value;
var st = number
st = number.substring( 0 , 1 );
if ( st== 2  || st== 5 ) 	
{
document.mform.city.options.length= 0 
document.mform.city.options[ 0 ]=new Option("мБОЗЕРБУ", "LANGEPAS", true, false)
document.mform.city.options[ 1 ]=new Option("рПЛБЮЙ", "POKACHI", false, false)
document.mform.city.options[ 2 ]=new Option("бзбо", "AGAN", false, false)
return false;
}