// JavaScript Document
function validar()
{
	if (document.forms['formu'].email.value=='')
	{
		alert("Por favor introduzca su e-mail");
		document.forms['formu'].email.focus();
		return false;
	}

	if ( document.forms['formu'].email.value.length >  0)	
	{
	if ( (document.forms['formu'].email.value.indexOf("@") < 0) || (document.forms['formu'].email.value.indexOf(".") < 0) || (document.forms['formu'].email.value.indexOf("@") > document.forms['formu'].email.value.lastIndexOf("."))|| (document.forms['formu'].email.value.length < 5) || (document.forms['formu'].email.value.indexOf(" ") >= 0))
		{
			alert("Email no válido");
			document.forms['formu'].email.focus();
			return false;
		}
	}	
}