jQuery & JavaScript

Read a QueryString value in the browser (JavaScript and jQuery)

jQuery & JavaScript · By the Postback Notes editorial team · Published 2026-09-10

Scripts often need a value from the page URL: orders.aspx?status=open&page=2. ASP.NET reads it with Request.QueryString on the server; in the browser, the standard URLSearchParams object does the same job, decoding included. jQuery has no helper for it and does not need one.

URLSearchParams

// URL: /orders.aspx?status=open&page=2&tag=a&tag=b&q=caf%C3%A9+cr%C3%A8me
var params = new URLSearchParams(window.location.search);

params.get("status");     // "open"
params.get("page");       // "2" (always a string)
params.get("missing");    // null
params.has("status");     // true
params.getAll("tag");     // ["a", "b"]
params.get("q");          // "café crème" (+ and %XX are decoded)

var page = parseInt(params.get("page"), 10) || 1;

Values are strings; convert them and supply defaults. getAll handles repeated keys, which get reduces to the first value.

Using it with jQuery

$(function () {
  var status = new URLSearchParams(location.search).get("status") || "all";
  $("#statusFilter").val(status);
  $(".tab[data-status='" + CSS.escape(status) + "']").addClass("active");
});

CSS.escape protects the selector against characters such as quotes in the value. Never write a query string value into the page with .html(): use .text() or .val(), or you create a cross-site scripting hole.

Older code: the regular-expression helper

Before URLSearchParams (supported by all current browsers, not by Internet Explorer), tutorials used a function like this. You will meet it in existing projects:

function getQueryValue(name) {
  var escaped = name.replace(/[.*+?^${}()|[\]\\]/g, "\\$&");
  var m = new RegExp("[?&]" + escaped + "=([^&#]*)").exec(location.search);
  return m ? decodeURIComponent(m[1].replace(/\+/g, " ")) : null;
}

Note the + replacement: in query strings produced by forms, a space is encoded as +, which decodeURIComponent alone does not convert.

Building a URL with parameters

var p = new URLSearchParams({ status: "open", page: 3 });
location.href = "orders.aspx?" + p.toString();   // status=open&page=3, encoded

The server decides

Anything a script reads from the URL, the server reads too, and the user can edit both. Use client-side values for display only, and validate them in the code-behind as shown in Passing multiple QueryString parameters. Values after # are a different part of the URL: see Read the URL hash.

Updating the URL without reloading

When a filter changes on the page, you can keep the URL in sync so that refreshing or sharing it restores the same view:

var params = new URLSearchParams(location.search);
params.set("status", "closed");
params.delete("page");
history.replaceState(null, "", location.pathname + "?" + params.toString());

replaceState changes the address bar without a new request or history entry; use pushState if the back button should return to the previous filter.

Official documentation