Summary of two methods for redirecting URL parameters in JavaScript

function setUri(para, val) {
      var strNewUrl = new String();
      var strUrl = new String();
      var url = window.location.href;
      strUrl = window.location.href;
 
      if (strUrl.indexOf("?") != -1) {
        strUrl = strUrl.substr(strUrl.indexOf("?") + 1);  //获取参数
 
        if (strUrl.toLowerCase().indexOf(para.toLowerCase()) == -1) { //如果没有找到参数,则直接赋值
          strNewUrl = url + "&" + para + "=" + val;
          window.location.href = strNewUrl;
        } else {
          var aParam = strUrl.split("&");
 
          for (var i = 0; i < aParam.length; i++) {
            if (aParam[i].substr(0, aParam[i].indexOf("=")).toLowerCase() == para.toLowerCase()) {
              aParam[i] = aParam[i].substr(0, aParam[i].indexOf("=")) + "=" + val;
            }
          }
          strNewUrl = url.substr(0, url.indexOf("?") + 1) + aParam.join("&");
          window.location.href = strNewUrl;
        }
      } else {
        strUrl += "?" + para + "=" + val;
        window.location.href = strUrl;
      }
    }

//使用正则
  function setPara(para, val) {
    var newpar = "";
    var url = window.location.href;
    var pars = location.search.substring(1);
 
    var reg = new RegExp("(^|)" + para + "=([^&]*)(|$)");
    if (reg.test(pars)) {  //有需要的参数para
 
      var p1 = pars.split(para)[0];  //productID=100857&count=1&
      var p2 = pars.split(para)[1];  //=75825&coupval=1.5&addressID=358&invoiceID=1245&invoiceName=jesse
 
      if (p2.indexOf("&") > -1) {
        var p3 = p2.split("&")[0];
        if (p3 == "=" + val + "") {
          return false;
        }
        newpar = p1 + para + '=' + val + '&' + (p2.split(p3))[1];
      } else {
        if (p1) {
          newpar = p1 + para + '=' + val;
        } else {
          newpar = para + '=' + val;
        }
      }
    } else {
      if (url.indexOf("?") == -1) {
        newpar = pars +"&"+ para + "=" + val;
      } else {
        newpar = pars + "&" + para + "=" + val;
      }
    }
    window.location.href = location.href.split('?')[0] + "?" + newpar;
  }

<script>
window.onload = function () {
      var btn = document.getElementById("btnClick");
 
      btn.onclick = function () {
 
　　　　　　　　　　// url地址:http://localhost:54714/testuri.aspx?productID=100857&count=1&coupresId=12785&coupval=1.5&openId=12456&addressID=358&invoiceID=&invoiceName=
　　　　　　　　　 //setUri("coupresId", 0);
　　　　　　　　　　setPara("coupresId", 0); 
　　　　} 
　　}
</script>
 
<input type="button" id="btnClick" value="重定义参数" />