var autofocussed = false;

function validate_form(form) {
	"use strict";
	
	autofocussed = false;
	var error = "";
	
	var filter = /^[^@]+@[^@.]+\.[^@]*\w\w$/ ;
				var illegal = /[\(\)\<\>\,\;\:\\"\[\]]/ ;
				var tfld = "";
					try {
						var field_contact_0 = form.elements["go_contactform_contact_field0"];
						if (field_contact_0.value.length < 2 || field_contact_0.value === "") {
							error = error + "\n- Voer een naam in (minimaal 2 tekens).";
							autofocus(field_contact_0);
						}
				} catch(e) { }
				
					try {
						var field_contact_1 = form.elements["go_contactform_contact_field1"];
						if (field_contact_1.value.length < 6 || field_contact_1.value === "") {
							error = error + "\n- Voer een e-mailadres in (minimaal 6 tekens).";
							autofocus(field_contact_1);
						}s = field_contact_1.value;
							tfld = s.replace(/^\s+|\s+$/, "");
							
							if (field_contact_1.value !== "" && (!filter.test(tfld) || s.match(illegal))) {
								error = error + "\n- Voer een juist e-mailadres in.";
								autofocus(field_contact_1);
							}
				} catch(e) { }
				
					try {
						var field_contact_2 = form.elements["go_contactform_contact_field2"];
						if (field_contact_2.value !== "" && field_contact_2.value.length < 10) {
							error = error + "\n- Voer een telefoonnummer in (minimaal 10 tekens) of laat dit veld leeg.";
							autofocus(field_contact_2);
						}if (field_contact_2.value !== "" && field_contact_2.value.replace(/[^0-9]/g, "").length < 10) { 
								error = error + "\n- Voer een juist telefoonnummer in of laat dit veld leeg.";
								autofocus(field_contact_2);
							}
				} catch(e) { }
				
					try {
						var field_contact_3 = form.elements["go_contactform_contact_field3"];
						if (field_contact_3.value.length < 3 || field_contact_3.value === "") {
							error = error + "\n- Voer een onderwerp in (minimaal 3 tekens).";
							autofocus(field_contact_3);
						}
				} catch(e) { }
				
					try {
						var field_contact_4 = form.elements["go_contactform_contact_field4"];
						if (field_contact_4.value.length < 10 || field_contact_4.value === "") {
							error = error + "\n- Voer een bericht in (minimaal 10 tekens).";
							autofocus(field_contact_4);
						}
				} catch(e) { }
				//captcha (comment en contactformulier)
		try {
			var captcha = form.elements.captcha;
			
			if (captcha.value.length < 4 ) {
				error = error + "\n- Voer de code (4 tekens) in.";
				autofocus(captcha);
			}
		}
		catch(e) { }	//comment (comment)
	try {
		var comment = form.elements.comment;
		
		if (comment.value.length < 5) {
			error = error + "\n- U kunt geen (bijna) lege reactie plaatsen.";
			autofocus(comment);
		}
	}
	catch(e) { }
	//email (comment)
	try {
		var email = form.elements.email;
		
		if (email.value.length < 5) {
			error = error + "\n- Voer uw e-mailadres in.";
			autofocus(email);
		}
		else {
			s = email.value;
			tfld = s.replace(/^\s+|\s+$/, "");
			
			if (!filter.test(tfld) || s.match(illegal)) {
				error = error + "\n- Voer een correct e-mailadres in.";
				autofocus(email);
			}
		}
	}
	catch(e) { }
	//auteur (comment)
	try {
		var author = form.elements.author;
		
		if (author.value.length < 2) {
			error = error + "\n- Voer uw naam in.";
			autofocus(author);
		}
	}
	catch(e) { }
	//zoekopdracht (search)
	try {
		var search = form.elements.search;
		
		if (search.value.length < 3) {
			error = error + "\n- U kunt geen (bijna) lege zoekopdracht opgeven.";
			autofocus(search);
		}
	}
	catch(e) { }
	
	//toon errors (als die er zijn)
	if(error === "") {
		return true;
	}
	else {
		alert("U heeft niet alle velden juist en/of volledig ingevuld:" + error);
		return false;
	}
}

function autofocus(element_id) {
	"use strict";

	if (autofocussed === false) {
		element_id.focus();
		autofocussed = true;
	}
}