JavaScript从url中获取指定query string的值

getUrlParameterByName.js

function getParameterByName(name, url) {
    if (!url) url = window.location.href;
    name = name.replace(/[\[\]]/g, "\\$&");
    var regex = new RegExp("[?&]" + name + "(=([^&#]*)|&|#|$)"),
        results = regex.exec(url);
    if (!results) return null;
    if (!results[2]) return '';
    return decodeURIComponent(results[2].replace(/\+/g, " "));
}


// example
<script src="http://localhost:8080/static/test.js?u=http://localhost:8080/api/get"></script>
var api = "";
var scripts = document.getElementsByTagName("script");
if (scripts && scripts.length > 0) {
     for (let i = 0; i < scripts.length; i++) {
         if (scripts[i].src.indexOf("ictr") !== -1) {
             api = getParameterByName("u", scripts[i].src);
         }
     }
}
console.log(api)  // http://localhost:8080/api/get