function validate_form ( )
{
	
		if ( document.order_form.Boiler.checked == "" )
    	{
        alert ( "Please indicate which Boiler you require." );
        return false;
    	}
		
		if ( document.order_form.Flue_Options.checked == false )
    	{
        alert ( "Please indicate which Flue Kit you require." );
        return false;
    	}
		
		if ( document.order_form.Delivery.checked == false )
    	{
        alert ( "Please indicate which delivery zone for your delivery." );
        return false;
    	}
		
        if ( document.order_form.Nextdaydelivery.checked == false )
    	{
        alert ( "Please advise us if you require Standard or Next Day delivery." );
        return false;
    	}
		
		if ( document.order_form.Boiler.selectedIndex == 0)
    {
        		alert ( "Please advise us of your Boiler requirements." );
				order_form.Boiler.focus();
        return false;
    }
		
		if ( document.order_form.Flue_Options.selectedIndex == 0)
    {
        		alert ( "Please advise us of your Flue Kit requirements." );
				order_form.Flue_Options.focus();
        return false;
    }
	
	    if ( document.order_form.Delivery.selectedIndex == 0)
    {
        		alert ( "Please advise us of your Delivery Zone" );
				order_form.Delivery.focus();
        return false;
    }
		
		if ( document.order_form.Nextdaydelivery.selectedIndex == 0)
    {
        		alert ( "Please advise us if you require Standard or Next Day delivery." );
				order_form.Nextdaydelivery.focus();
        return false;
    }
		
		if ( document.order_form.Payment.selectedIndex == 0)
    {
        		alert ( "Please advise how you wish to pay" );
				order_form.Payment.focus();
        return false;
    }
		
		if ( document.order_form.Name.value == "" )
        {
                alert ( "Please fill in the your Name." );
				order_form.Name.focus();
                return false;
        }
		
		if ( document.order_form.Name.value == "Name" )
        {
                alert ( "Please fill in the your Name." );
				order_form.Name.focus();
                return false;
        }
		
		if ( document.order_form.youremail.value == "" )
        {
                alert ( "Please enter a valid email address" );
				order_form.youremail.focus();
                return false;
        }
		
		if ( document.order_form.youremail.value == "Email address" )
        {
                alert ( "Please enter a valid email address" );
				order_form.youremail.focus();
                return false;
        }
		
		if (!/^\w+([\.-]?\w+)*@\w+([\.-]?\w+)*(\.\w{2,3})+$/.test(order_form.youremail.value)){
		alert("Please enter a valid email address" );
		order_form.youremail.focus();
		return false;
		}

        if ( document.order_form.Telephone_Day.value == "" )
        {
                alert ( "Please fill in your Daytime Telephone Number." );
				order_form.Telephone_Day.focus();
                return false;
        }
		
		if ( document.order_form.Telephone_Day.value == "Telephone (Day)" )
        {
                alert ( "Please fill in your Daytime Telephone Number." );
				order_form.Telephone_Day.focus();
                return false;
        }

        if ( document.order_form.Telephone_Mobile.value == "" )
        {
                alert ( "Please fill in your Mobile Telephone Number." );
				order_form.Telephone_Mobile.focus();
                return false;
        }
		
		if ( document.order_form.Telephone_Mobile.value == "Telephone (Mobile)" )
        {
                alert ( "Please fill in your Mobile Telephone Number." );
				order_form.Telephone_Mobile.focus();
                return false;
        }

        if ( document.order_form.Delivery_Address.value == "" )
        {
                alert ( "Please fill in your Delivery Address." );
				order_form.Delivery_Address.focus();
                return false;
        }
		
		if ( document.order_form.Delivery_Address.value == "Delivery Address" )
        {
                alert ( "Please fill in your Delivery Address." );
				order_form.Delivery_Address.focus();
                return false;
        }
		
		if ( document.order_form.Postcode.value == "" )
        {
                alert ( "Please fill in your Postcode." );
				order_form.Postcode.focus();
                return false;
        }
		
		if ( document.order_form.Postcode.value == "Postcode" )
        {
                alert ( "Please fill in your Postcode." );
				order_form.Postcode.focus();
                return false;
        }
		
		if ( document.order_form.Sub.value == "" )
        {
                alert ( "Please fill in your Subject." );
				order_form.Sub.focus();
                return false;
        }
		
		if ( document.order_form.Sub.value == "Subject" )
        {
                alert ( "Please fill in your Subject." );
				order_form.Sub.focus();
                return false;
        }
		
		if ( document.order_form.Delivery_town.value == "" )
        {
                alert ( "Please advise us of your approximate delivery Town / City / Postcode." );
				order_form.Delivery_town.focus();
                return false;
        }
		
		if ( document.order_form.Delivery_town.value == "Delivery Town / City / Postcode" )
        {
                alert ( "Please advise us of your approximate delivery Town / City / Postcode." );
				order_form.Delivery_town.focus();
                return false;
        }
		
		if ( document.order_form.Question.value == "" )
        {
                alert ( "Please type your question in the box provided." );
				order_form.Question.focus();
                return false;
        }
		
		if ( document.order_form.Question.value == "Please type your question here" )
        {
                alert ( "Please type your question in the box provided." );
				order_form.Question.focus();
                return false;
        }
		
		if ( document.order_form.Submissioncode.value != "" )
        {
                alert ( "Please leave this box Blank." );
                return false;
        }


        return true;
}