function emailEsValido(email)
{
	var reg_exp = new RegExp(/^[^@]+@[^@]+\.[^@]+$/);
	if (!reg_exp.test(email.value)) {
		alert('Email address is not valid. Please, check it');
		email.focus();
		return false;
	}
	else
		return true;
}

function passwordEsValido(password, confirm_password)
{
	var reg_exp = new RegExp(/^[a-zA-Z0-9_\-]+$/);
	if (password.value.length < 6 || password.value.length > 20) {
		alert("Password length must be 6 to 20. Please, check it");
		password.focus();
		return false;
	}
	else if (!reg_exp.test(password.value)) {
		alert("Password can only contain letters, digits, underscores or hyphens. Please, change it");
		password.focus();
		return false;
	}
	else if (password.value != confirm_password.value) {
		alert('"Password" and "Confirm password" fields missmatch. Please, check them');
		password.focus();
		return false;
	}
	else
		return true;
}

function nombreEsValido(name)
{
	if (name.value == '') {
		alert("Please, enter your Name or alias");
		name.focus();
		return false;
	}
	else if (name.value.length < 3) {
		alert("Name is too short. Please, enter at least 3 characters");
		name.focus();
		return false;
	}
	else
		return true;
}

function tituloEsValido(title)
{
	if (title.value == '') {
		alert("Please, enter the Title");
		title.focus();
		return false;
	}
	else if (title.value.length < 5) {
		alert("Title is too short. Please, enter at least 5 characters");
		title.focus();
		return false;
	}
	else
		return true;
}

function descripcionEsValida(description)
{
	if (description.value.length < 100 || description.value.length > 250) {
		alert("Description length must be 100 to 250 characters. Please, check it");
		descripcion.focus();
		return false;
	}
	else
		return true;
}

function perfilEsValido(title, description)
{
	if (title.value == '' || description.value == '') {
		alert('Please, fill the profile out properly');
		return false;
	}
	else
		return (tituloEsValido(title) && descripcionEsValida(description));
}

function urlEsValida(url)
{
	var url_aux = url.value.substring(7, url.value.length);
	var pos;
	if (url.value == 'http://' || url.value == '') {
		alert("Please, enter site's URL");
		url.focus();
		return false;
	}
	else if (url.value.substring(0, 7) != 'http://') {
		alert("Site's "+'URL should begin with "http://". Please correct it');
		url.focus();
		return false;
	}
	else if ((pos = url.value.lastIndexOf('/')) > 6 && (url_aux.indexOf('/') != url_aux.lastIndexOf('/') || url.value.length > (pos+1))) {
		alert("Site's URL should refer to domain's root folder."+"\n"+'Ex: "http://www.site.com/page7.html" is not allowed, it should be "http://www.site.com/"');
		url.focus();
		return false;
	}
	else
		return true;
}

function categoriaEsValida(category)
{
	if (category.value == '-') {
		alert("Please, choose site's category and subcategory");
		return false;
	}
	else
		return true;
}

function captchaEsValido(codigo)
{
	if (codigo.value.length < 6) {
		alert("Please, enter the security number properly");
		codigo.focus();
		return false;
	}
	else
		return true;
}