function validateEmpty(fld) {
    var error = "";
 
    if (fld.value.length == 0 || fld.value == "null") {
        fld.style.background = 'Red'; 
        error = fld.name + " \n"
    } else {
        fld.style.background = 'White';
    }
    return error;  
}

function validateNumericOnly(fld) {
	var error = "";
	var ValidChars = "0123456789. ";
	var IsNumber=true;
	var Char;
	
	for (i = 0; i < fld.value.length && IsNumber == true; i++) { 
		Char = fld.value.charAt(i); 
		if (ValidChars.indexOf(Char) == -1) {
			IsNumber=false;
		}
	}
	if(!IsNumber) {
		fld.style.background = 'Red'; 
		error += fld.name + " can only hold a number \n" ;	
	}
	
	return error;	
}
function validate_login()
{
        var error="";
        var field_name="";

        error += validateEmpty(document.login.email);
        if(document.login.email.value == "")
        field_name += "Email \n";

        error += validateEmpty(document.login.password);
        if(document.login.password.value == "")
        field_name += "Password \n";

        if(error)
        {
                        alert("The following field(s) are required:\n" + field_name);
                        return false;
        }

}

function validate_register()
{
        var error="";
        var field_name="";
        var error2="";
	var field_name2="";
        var invalid = " "; //check for white space in mobile number
 
	error += validateEmpty(document.register.email);
        if(document.register.email.value == "")
        field_name += "Email \n";

        error += validateEmpty(document.register.password);
        if(document.register.password.value == "")
        field_name += "Password \n";

	if(document.register.prayers.checked == true)
	{
        	error += validateEmpty(document.register.number);
	        if(document.register.number.value == "")
        	field_name += "Mobile Phone Number \n";
	}
	else
	{
		document.register.number.style.background = 'White';	
	}	
	
	error += validateEmpty(document.register.first_name);	
        if(document.register.first_name.value == "")
        field_name += "First Name \n";

        error += validateEmpty(document.register.surname);
        if(document.register.surname.value == "")
        field_name += "Surname \n";

	if(!error)
	{
		error2 += validateNumericOnly(document.register.number);
		field_name2+="Mobile Phone Number \n";
	}
        
	if(error)
        {
                        alert("The following field(s) are required:\n" + field_name);
                        return false;
        }
        if(error2)
        {
                alert("The following field should only be numbers (no characters or letters):\n" + field_name2);
                return false;
        }
        if((document.register.number.value.length != 0 && document.register.number.value.length != 11) || (document.register.number.value.indexOf(invalid) > -1))
        {
                alert("Wrong mobile number!! Should be 11 numbers only and make sure there are NO spaces(example: 07878778787).");
                return false;

        }
	
	if(document.register.events.checked == false && document.register.janazah.checked == false && document.register.prayers.checked == false)
	{
		alert("Please choose one of the alerts (Events, Janazah or Prayers Time Change)!!!");
		return false;
	}

}
function validate_update()
{
        var error="";
        var field_name="";
        var error2="";
        var field_name2="";

        error += validateEmpty(document.update.old_password);
        if(document.update.old_password.value == "")
        field_name += "Password \n";

        if(document.update.prayers.checked == true)
        {
        	error += validateEmpty(document.update.number);
        	if(document.update.number.value == "")
       		field_name += "Mobile Phone Number \n";
	}
        else
        {
                document.update.number.style.background = 'White';
        }


        error += validateEmpty(document.update.first_name);
        if(document.update.first_name.value == "")
        field_name += "First Name \n";

        error += validateEmpty(document.update.surname);
        if(document.update.surname.value == "")
        field_name += "Surname \n";

        error2 += validateNumericOnly(document.update.number);
        field_name2+="Mobile Phone Number \n";

        if(error)
        {
                        alert("The following field(s) are required:\n" + field_name);
                        return false;
        }

        if(error2)
        {
                alert("The following field should only be numbers (no characters or letters):\n" + field_name2);
                return false;
        }
        if((document.update.number.value.length != 0 && document.update.number.value.length != 11) || (document.update.number.value.indexOf(invalid) > -1))
        {
                alert("Wrong mobile number!! Should be 11 numbers only and make sure there are NO spaces(example: 07878778787).");
                return false;
        }

        if(document.update.events.checked == false && document.update.janazah.checked == false && document.update.prayers.checked == false)
        {
                var answer = confirm("Are you sure you want to unsubscribe!!!");
                if (answer == true)
                {
                        return true;
                }
                else
                {
                        return false;
                }

        }

}