我开发了一个函数,调用时应该打开一个窗口,但它会返回null。如果我在原始 JavaScript 函数中打开窗口,它就可以工作。我想它是将控制权传递给另一个函数的原始函数,但由于某种原因这不起作用。
这是我的原始函数,这基本上调用了一个新的 JavaScript 文件并加载了一个 HTML 文件,当“就绪”时,它需要显示 window.open 以及现在为字符串形式的 HTML 文件。
order.prototype.printMe = function() {
    order_resume.loadthis("myTestPage.html", "showData");
    // OPENING WINDOW HERE WORKS; but the the html file that is loaded
    // in above line hasn't finsihed loading - so i need to show it form
    // the function below once in "ready" state 
/*      child1 = window.open ("about:blank","_blank");
        child1.document.write( myDocument );
        child1.document.close();
*/      
}
这是我从原始函数调用的函数:
function showResume() {
    this.req = false;
    reservaResumen.prototype.showData = function() {
        if (this.req.readyState == 4) {
            child1 = window.open("about:blank", "_blank"); /// THIS RETURNS NULL
            child1.document.write("test");
            child1.document.close();
        }
    }
    reservaResumen.prototype.loadthis = function(url, myMethod) {
        if (window.XMLHttpRequest && !(window.ActiveXObject)) {
            try {
                this.req = new XMLHttpRequest();
            }
            catch (e) {
                this.req = false;
            }
        }
        else if (window.ActiveXObject) {
            try {
                this.req = new ActiveXObject("Msxml2.XMLHTTP");
            }
            catch (e) {
                try {
                    this.req = new ActiveXObject("Microsoft.XMLHTTP");
                }
                catch (e) {
                    this.req = false;
                }
            }
        }
        if (this.req) {
            var loader = this;
            this.req.onreadystatechange = function() {
                eval("loader." + myMethod + ".call(loader)")
            }
            this.req.open("GET", url, true);
            this.req.send("");
        }
    }