var Errors = "";

function checkForm()
{

        Errors="";

        surname();
        userid();
        telephone();

        if(Errors.length != "")
        {
                pageHeader();
                pageFooter();

                error_window = window.open("", "errors", 'width=550, height=300');
                error_window.document.write("ERRORS:\n");
                error_window.document.write(Errors);
                error_window.document.close();
                return false;
        }
        else
                return true;
}

function telephone()
{
        var f03 = document.pizza.field03.value;
        var pnumlength = f03.length;

        if(f03.value == "")
        {
                Errors += ' <li>
}


function userid()
{
        var f02 = document.pizza.field02.value;
        var idlength = f02.length;
        var wrong = 1;
        var wrong2;
        var total1 = 0;
        var total2 = 0;

//RULE 1

        if(f02.charCodeAt(0) != 65 && f02.charCodeAt(0) != 70)
        {
                Errors += ' <li> The first letter in the user ID must be either "A" or "F"\n </li>';
        }

//RULE 2

        for(var i=1; i < 6; i++)
        {
                if(f02.charCodeAt(i) > 48 && f02.charCodeAt(i) < 57)
                {
                        wrong = 0;

                        total1 += f02.charAt(i);
                }
                else
                {
                        wrong = 1;
                }
        }

        if(wrong==1)
        {
                Errors += ' <li> In the user ID there must be 5 digits after the first character\n </li>'
        }

//RULE 3

        if(f02.charCodeAt(6) != 45)
        {
                Errors += ' <li> In The user ID the seventh character must be a hyphen "-"\n </li>'
        }

//RULE 4

        for(var n=7; n < 12; n++)
        {
                if(f02.charCodeAt(n) > 48 && f02.charCodeAt(n) < 57)
                {
                        wrong2 = 0;
                        total2 += f02.charAt(n);
                }
                else
                {
                        wrong2 = 1;
                }
        }

        if(wrong2==1)
        {
                Errors += ' <li> In the user ID there must be 5 digits after the hyphen\n </li>'
        }

//RULE 5

        if(total1 < total2)
        {
                Errors += ' <li> The first 5 digits in the user ID must add up to less than the second 5 digits\n </li>'
        }

}


function surname()
{
        var f01 = document.pizza.field01.value;
        var F01 = document.getElementById('field01');
        var name_len = f01.length;
        var counters = 0;


        for(var i=0 ; i <= name_len-1; i++)
        {
                if(f01.charCodeAt(i) < 65 || f01.charCodeAt(i) > 90 && f01.charCodeAt(i) < 97 || f01.charCodeAt(i) > 122)
                {
                        counters=1;
                }
        }

        if(counters==1)
        {
                        Errors += " <li> Client Surname must contain only alphabetic characters(a-z) (A-Z) </li>\n";
        }

        if(F01.value == "")
        {
                Errors += " <li> Must enter a surname </li>\n";
        }

        if(name_len < 4)
        {
                Errors += " <li> Client Surname must have at least 4 alphabetic characters (a-z) (A-Z) </li> \n";
        }
}



     function pageHeader() {
       content = '<?xml version="1.0"encoding="UTF-8" ?>\n';
       content += '<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"\n';
       content += '"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">\n';
       content += ' <html xmlns="http://www.w3.org/1999/xhtml">\n';
       content += '  <head>\n';
       content += '   <title>form validation</title>\n';
       content += '  </head>\n';
       content += '  <body>\n';
       content += '   <h3>Please correct the following and resubmit the form</h3>\n';
       content += '   <ul>\n';
       return content;
     }


     function pageFooter() {
       content += '   </ul>\n';
       content += '  </body>\n';
       content += ' </html>\n';
       return content;
     }