JSFiddle - React, Tailwind, and code Playground

JavaScript

var url = "http://www.testUrl.com/?kerdesPost=fdasdas%20ad%20asd%20ad%20asdas";

if((url).indexOf('?') != -1) {
    var queryString = (url).substr((url).indexOf('?') + 1); 

    // "queryString" will now contain kerdesPost=fdasdas%20ad%20asd%20ad%20asdas

    var value = (queryString.split('='))[1];

    // "value" will now contain fdasdas%20ad%20asd%20ad%20asdas

    value = decodeURIComponent(value);

    // "value" will now contain fdasdas ad asd ad asdas (unescaped value)
}

alert(value);