layui.js 如何声明全局变量

//这段代码通用：

var url = location.search; //获取url中"?"符后的字串

    var theRequest = new Object();

    if (url.indexOf("?") != -1) {

      var str = url.substr(1);

      strs = str.split("&");

      for (var i = 0; i < strs.length; i++) {

        theRequest[strs[i].split("=")[0]] = unescape(strs[i].split("=")[1]);

      }

    }

    var $proId = theRequest.projectId;  //声明全局项目id