javascript JSONP 跨域请求

            //JSONP调用
            function JSONP(params){
                try {
                    var url = params;
                    var oldScript = document.getElementById(params);
                    if (oldScript) {
                        document.getElementsByTagName("head")[0].removeChild(oldScript);
                    }
                    var script = document.createElement("script");
                    script.setAttribute("type", "text/javascript");
                    script.setAttribute("src", url);
                    script.setAttribute("id", params);
                    document.getElementsByTagName("head")[0].appendChild(script);
                }
                catch (e) {
                    widgets.base.whenErrorShowInHTML(document.getElementById("initDiv"), e);
                }
            }