有时我们看到?在URL结尾，我找到了一些解决方案，生成的结果为file.php?&foo=bar。我想出了我自己的解决方案，以完美地工作!

location.origin + location.pathname + location.search + (location.search=='' ? '?' : '&') + 'lang=ar'

注意:位置。origin不能在IE中工作，这里是它的修复。

试一试 正则表达式，如此之慢，因此:

var SetParamUrl = function(_k, _v) {// replace and add new parameters

    let arrParams = window.location.search !== '' ? decodeURIComponent(window.location.search.substr(1)).split('&').map(_v => _v.split('=')) : Array();
    let index = arrParams.findIndex((_v) => _v[0] === _k); 
    index = index !== -1 ? index : arrParams.length;
    _v === null ? arrParams = arrParams.filter((_v, _i) => _i != index) : arrParams[index] = [_k, _v];
    let _search = encodeURIComponent(arrParams.map(_v => _v.join('=')).join('&'));

    let newurl = window.location.protocol + "//" + window.location.host + window.location.pathname + (arrParams.length > 0 ? '?' +  _search : ''); 

    // window.location = newurl; //reload 

    if (history.pushState) { // without reload  
        window.history.pushState({path:newurl}, null, newurl);
    }

};

var GetParamUrl = function(_k) {// get parameter by key

    let sPageURL = decodeURIComponent(window.location.search.substr(1)),
        sURLVariables = sPageURL.split('&').map(_v => _v.split('='));
    let _result = sURLVariables.find(_v => _v[0] === _k);
    return _result[1];

};

例子:

        // https://some.com/some_path
        GetParamUrl('cat');//undefined
        SetParamUrl('cat', "strData");// https://some.com/some_path?cat=strData
        GetParamUrl('cat');//strData
        SetParamUrl('sotr', "strDataSort");// https://some.com/some_path?cat=strData&sotr=strDataSort
        GetParamUrl('sotr');//strDataSort
        SetParamUrl('cat', "strDataTwo");// https://some.com/some_path?cat=strDataTwo&sotr=strDataSort
        GetParamUrl('cat');//strDataTwo
        //remove param
        SetParamUrl('cat', null);// https://some.com/some_path?sotr=strDataSort

我喜欢穆罕穆德·法提赫·耶尔达兹的回答，即使他没有回答整个问题。

在他回答的同一行中，我使用了这样的代码:

“它不控制参数的存在，也不改变现有的值。它把你的参数加到最后"

  /** add a parameter at the end of the URL. Manage '?'/'&', but not the existing parameters.
   *  does escape the value (but not the key)
   */
  function addParameterToURL(_url,_key,_value){
      var param = _key+'='+escape(_value);

      var sep = '&';
      if (_url.indexOf('?') < 0) {
        sep = '?';
      } else {
        var lastChar=_url.slice(-1);
        if (lastChar == '&') sep='';
        if (lastChar == '?') sep='';
      }
      _url += sep + param;

      return _url;
  }

测试者:

  /*
  function addParameterToURL_TESTER_sub(_url,key,value){
    //log(_url);
    log(addParameterToURL(_url,key,value));
  }

  function addParameterToURL_TESTER(){
    log('-------------------');
    var _url ='www.google.com';
    addParameterToURL_TESTER_sub(_url,'key','value');
    addParameterToURL_TESTER_sub(_url,'key','Text Value');
    _url ='www.google.com?';
    addParameterToURL_TESTER_sub(_url,'key','value');
    _url ='www.google.com?A=B';
    addParameterToURL_TESTER_sub(_url,'key','value');
    _url ='www.google.com?A=B&';
    addParameterToURL_TESTER_sub(_url,'key','value');
    _url ='www.google.com?A=1&B=2';
    addParameterToURL_TESTER_sub(_url,'key','value');

  }//*/

加入@Vianney的回答https://stackoverflow.com/a/44160941/6609678

我们可以导入node中的内置URL模块，如下所示

const { URL } = require('url');

例子:

Terminal $ node
> const { URL } = require('url');
undefined
> let url = new URL('', 'http://localhost:1989/v3/orders');
undefined
> url.href
'http://localhost:1989/v3/orders'
> let fetchAll=true, timePeriod = 30, b2b=false;
undefined
> url.href
'http://localhost:1989/v3/orders'
>  url.searchParams.append('fetchAll', fetchAll);
undefined
>  url.searchParams.append('timePeriod', timePeriod);
undefined
>  url.searchParams.append('b2b', b2b);
undefined
> url.href
'http://localhost:1989/v3/orders?fetchAll=true&timePeriod=30&b2b=false'
> url.toString()
'http://localhost:1989/v3/orders?fetchAll=true&timePeriod=30&b2b=false'

有用的链接:

https://developer.mozilla.org/en-US/docs/Web/API/URL https://developer.mozilla.org/en/docs/Web/API/URLSearchParams

感谢大家的贡献。我使用annakata代码并修改为也包括url中根本没有查询字符串的情况。 希望这能有所帮助。

function insertParam(key, value) {
        key = escape(key); value = escape(value);

        var kvp = document.location.search.substr(1).split('&');
        if (kvp == '') {
            document.location.search = '?' + key + '=' + value;
        }
        else {

            var i = kvp.length; var x; while (i--) {
                x = kvp[i].split('=');

                if (x[0] == key) {
                    x[1] = value;
                    kvp[i] = x.join('=');
                    break;
                }
            }

            if (i < 0) { kvp[kvp.length] = [key, value].join('='); }

            //this will reload the page, it's likely better to store this until finished
            document.location.search = kvp.join('&');
        }
    }

在URL类中有一个内置函数，你可以使用它来轻松处理查询字符串的键/值参数:

const url = new URL(window.location.href);
// url.searchParams has several function, we just use `set` function
// to set a value, if you just want to append without replacing value
// let use `append` function

url.searchParams.set('key', 'value');

console.log(url.search) // <== '?key=value'

// if window.location.href has already some qs params this `set` function
// modify or append key/value in it

有关searchParams函数的更多信息。

IE不支持URL，请检查兼容性