Esta es mi aportacion, dependiendo de tus requisitos pudiera modificarla ampliamente:
   Código HTML:
 <input type="text" id="numero">
<script type="text/javascript">
function numerosEnterosTelefono(e) {
	var e = e || window.event;
	var code = e.which || e.keyCode;
	var character = String.fromCharCode(code);
	
	if (code === 116 || code === 17 || code === 37 ||  code === 39 || code === 8 || code === 9 || code === 13 || code === 27 || code === 46 || /\d/.test(character)) {
		return true;
	}
	else {
		return false;
	}
}
document.getElementById('numero').onkeypress = numerosEnterosTelefono;
</script>