function resettext(text)
{
if (text=="Escribe tu busqueda")
	{ document.getElementById('s').value=""; }
          document.getElementById('s').style.color = "black";
}

document.oncontextmenu = function(){return false}
<!-- SELECCION DE TEXTO-->
// IE Evitar seleccion de texto
document.onselectstart=function(){
if (event.srcElement.type != "text" && event.srcElement.type != "textarea" && event.srcElement.type != "password")
return false
else return true;
};

// FIREFOX Evitar seleccion de texto
if (window.sidebar){
document.onmousedown=function(e){
document.body.style.cursor = 'default'
var obj=e.target;
if (obj.tagName.toUpperCase() == "INPUT" || obj.tagName.toUpperCase() == "TEXTAREA" || obj.tagName.toUpperCase() == "PASSWORD")
return true;
/*else if (obj.tagName=="BUTTON"){
return true;
}*/
else
document.body.style.cursor = 'default'
return false;
}
}

<!-- EVITAR IFRAME-->
<!--// evito que se cargue en otro frame
if (parent.frames.length > 0) top.location.replace(document.location);
//-->
<!-- EVITAR DRAG AND DROP-->
<!-- Begin
document.ondragstart = function(){return false}
// End -->