[dolte]

Разобрался

var request1 = new XMLHttpRequest();
	request1.open('GET', 'page1.html');
var request2 = new XMLHttpRequest();
	request2.open('GET', 'page2.html');
var request3 = new XMLHttpRequest();
	request3.open('GET', 'page3.html');
var request4 = new XMLHttpRequest();
	request4.open('GET', 'page4.html');
var request5 = new XMLHttpRequest();
	request5.open('GET', 'page5.html');
		request1.send(null)
		request2.send(null)
		request3.send(null)
		request4.send(null)
		request5.send(null)
var html = document.documentElement;

window.onscroll = function ()
{
var B = document.body, 
    DE = document.documentElement,
    O = Math.min (B.clientHeight, DE.clientHeight); if (!O) O = B.clientHeight;
var S = Math.max (B.scrollTop, DE.scrollTop),
    C = Math.max (B.scrollHeight, DE.scrollHeight);

var element1 = document.querySelector('.contentBody1');
var element2 = document.querySelector('.contentBody2');
var element3 = document.querySelector('.contentBody3');
var element4 = document.querySelector('.contentBody4');
var element5 = document.querySelector('.contentBody5');
if ($(this).scrollTop() >= 650) 
        {
				element1.innerHTML = request1.responseText;
        }
if ($(this).scrollTop() >= 2500) 
        {
				element2.innerHTML = request2.responseText;
        }
	//element5.innerHTML = request5.responseText;
	//element4.innerHTML = request4.responseText;
	//element3.innerHTML = request3.responseText;
	//element2.innerHTML = request2.responseText;
	//element1.innerHTML = request1.responseText;
}