var autofocussed = false;

function validate_form(form) {
	"use strict";
	
	autofocussed = false;
	var error = "";
	
	var filter = /^[^@]+@[^@.]+\.[^@]*\w\w$/ ;
				var illegal = /[\(\)\<\>\,\;\:\\"\[\]]/ ;
				var tfld = "";//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;
	}
}