JSFiddle - React, Tailwind, and code Playground

HTML

<div>
<button style="float:left;" id="previousP">Previous</button>
<input id="manual" style="margin-left:100px;float:left;" type="text" value="10000" /><button style="float:left;" id="Go">Go</button>
<button style="float:right;" id="nextP">Next</button>
<div style="clear:both">
<iframe id="trumpVision" style="width:100%;height:600px" src="https://wikileaks.org/dnc-emails/emailid/10000">
</iframe>
</div>
</div>

JavaScript

$("#nextP").click(function(){
	var pageUrl = $("#trumpVision").attr("src");
	var currentPage = parseInt(pageUrl.substring(pageUrl.lastIndexOf("/")+1));
  changePage(currentPage + 1);
});

$("#previousP").click(function(){
	var pageUrl = $("#trumpVision").attr("src");
	var currentPage = parseInt(pageUrl.substring(pageUrl.lastIndexOf("/")+1));
  changePage(currentPage - 1);
});

$("#Go").click(function(){
	var currentPage = parseInt($("#manual").val());
	changePage(currentPage);
});

function changePage(pageNumber){
	$("#trumpVision").attr("src","https://wikileaks.org/dnc-emails/emailid/" + pageNumber);
  $("#manual").val(pageNumber);
}