How to ask for a specific element using Xmlhttprequest parameters

Question

The element I am looking for:

<h1 id="itemSummaryPrice" style="color: rgb(255, 255, 255);">42 - 47</h1>

I wanna make a chrome extension that uses XMLHttpRequest GET METHOD for checking a value on another Website, i know i can give the URL, parameters for scaling down the response. So my question is how do I make an URL that gives me only the element in the response that I am looking for ? if its even possible.

Answer 1

You can't request only one part (node) of a document. You'll have to request the whole thing, parse it then select from it what you want:

var request = new XMLHttpRequest();
request.open("GET", yourUrl);

request.onload = function() {
    var doc = new DOMParser().parseFromString(request.responseText, "text/html");
    var el = doc.getElementById("itemSummaryPrice"); // the element you want
}

request.send(null);

Or you can set the responseType to "document" and let the XMLHttpRequest do the parsing internally, then use responseXML:

var request = new XMLHttpRequest();
request.open("GET", yourUrl);
request.responseType = "document";

request.onload = function() {
    var doc = request.responseXML;
    var el = doc.getElementById("itemSummaryPrice"); // the element you want
}

request.send(null);