function enviar(){
    var d = document.getElementById("dia");
    var m = document.getElementById("mes");
    var y = document.getElementById("anio");
    
    if(d.value == "" || m.value == "" || y.value == ""){    
        return false;
    }else{
        document.getElementById("frm_date").submit();
    }
    
    return false;
    
}
function permite(elElvento){
	var numeros = "0123456789";
	var teclas_especiales = [8, 37, 39, 46];
    
	var evento = elElvento || window.event;
	var codigoCaracter = evento.charCode || evento.keyCode;
	var caracter = String.fromCharCode(codigoCaracter);

	var tecla_especial = false;
	
	for(var i in teclas_especiales){
		if(codigoCaracter == teclas_especiales[i]){
			tecla_especial = true;
			break;
		}
	} 
	return numeros.indexOf(caracter) != -1 || tecla_especial;
}	

function trim(text) {
    return text.replace(/^\s+|\s+$/g, "");
}

var form = document.getElementsByTagName('form');
var input = form[0].getElementsByTagName('input');
var btn = form[0].getElementsByTagName('button');

var error = document.createElement('h3');
form[0].appendChild(error);
error.style.background="none";
var valido = true;
var anio = new Date();
anio = anio.getFullYear();

for(var i=0; i<3; i++){
    input[i].onblur = function(){
        if(trim(this.value) == ''){
            valido = false;
        }else{
            switch(this.name){
                case 'dia':
                    if(this.value<0 || this.value>31){
                           valido = false;
                    }else{
                        valido = true;
                    }
                    break;
                case 'mes':
                    if(this.value<0 || this.value>12){
                           valido = false;
                    }else{
                        valido = true;
                    }
                    break;
                case 'anio':
                    if(this.value<1900   || this.value>(anio-18)){
                           valido = false;
                    }else{
                        valido = true;
                    }
                    break;
            }
        
        }            

        if(valido){
            habilitar();
        }else{
            deshabilitar();
        }
    }
}

    function deshabilitar(){
        btn[0].disabled = true;
        error.innerHTML = 'fecha incorrecta';
        error.style.background="url('/_images/sprite.png') no-repeat 0px -118px";
    }
    
    function habilitar(){
        btn[0].disabled = false;
        error.style.background="none";
        error.innerHTML = ''; 
    }