/* these functions are used to check various form fields ( created by S. T. for GSC).
*/
/* e-mails are build like x1@x2.x3 where x1&x2>=1 and x3>1 (x3 can be 4 (e.g. mail@mail.info))*/
function valid_mail(form_name, field_name, alert_message) 
{
	eval('var input_str=document.'+ form_name +'.'+ field_name +'.value;');
	var input_lenght=input_str.length;
	if (input_lenght>0)
	{
		at_index=input_str.indexOf('@');
		lastdot_index=input_str.lastIndexOf('.');
		if (at_index<1||lastdot_index<3||at_index>lastdot_index||lastdot_index>(input_lenght-2))
		{
			alert(alert_message);
		}
	}
}
/* compares password and retyped password, alerts message if not equal, also alerts if less than 5 symbols. */
function compare_password(pass_field1, pass_field2, alert_message1, alert_message2)
{
	eval('var input_str1=document.form_register.'+ pass_field1 +'.value;');
	eval('var input_str2=document.form_register.'+ pass_field2 +'.value;');
	
	if (input_str1!==input_str2)
	{
		alert(alert_message1);
	}
	if (input_str1.length<5) { alert(alert_message2); }
}