How can I delete a query string parameter in JavaScript?

"[&;]?" + parameter + "=[^&;]+"

Seems dangerous because it parameter ‘bar’ would match:

?a=b&foobar=c

Also, it would fail if parameter contained any characters that are special in RegExp, such as ‘.’. And it's not a global regex, so it would only remove one instance of the parameter.

I wouldn't use a simple RegExp for this, I'd parse the parameters in and lose the ones you don't want.

function removeURLParameter(url, parameter) {    //prefer to use l.search if you have a location/link object    var urlparts = url.split('?');       if (urlparts.length >= 2) {        var prefix = encodeURIComponent(parameter) + '=';        var pars = urlparts[1].split(/[&;]/g);        //reverse iteration as may be destructive        for (var i = pars.length; i-- > 0;) {                //idiom for string.startsWith            if (pars[i].lastIndexOf(prefix, 0) !== -1) {                  pars.splice(i, 1);            }        }        return urlparts[0] + (pars.length > 0 ? '?' + pars.join('&') : '');    }    return url;}

Modern browsers provide URLSearchParams interface to work with search params. Which has delete method that removes param by name.

if (typeof URLSearchParams !== 'undefined') {  const params = new URLSearchParams('param1=1&param2=2&param3=3')    console.log(params.toString())    params.delete('param2')    console.log(params.toString())} else {  console.log(`Your browser ${navigator.appVersion} does not support URLSearchParams`)}