JavaScript_js模拟键盘输入

function fireKeyEvent(el, evtType, keyCode) {
            var evtObj;
            if (document.createEvent) {
                if (window.KeyEvent) {//firefox 浏览器下模拟事件
                    evtObj = document.createEvent('KeyEvents');
                    evtObj.initKeyEvent(evtType, true, true, window, true, false, false, false, keyCode, 0);
                } else {//chrome 浏览器下模拟事件
                    evtObj = document.createEvent('UIEvents');
                    evtObj.initUIEvent(evtType, true, true, window, 1);

                    delete evtObj.keyCode;
                    if (typeof evtObj.keyCode === "undefined") {//为了模拟keycode
                        Object.defineProperty(evtObj, "keyCode", { value: keyCode });                       
                    } else {
                        evtObj.key = String.fromCharCode(keyCode);
                    }

                    if (typeof evtObj.ctrlKey === 'undefined') {//为了模拟ctrl键
                        Object.defineProperty(evtObj, "ctrlKey", { value: true });
                    } else {
                        evtObj.ctrlKey = true;
                    }
                }
                el.dispatchEvent(evtObj);

            } else if (document.createEventObject) {//IE 浏览器下模拟事件
                evtObj = document.createEventObject();
                evtObj.keyCode = keyCode
                el.fireEvent('on' + evtType, evtObj);
            }
        }
        
        var testPassword = "181818";
        var tp;
        var cCode;
        var testss = document.getElementById("input_txt_50531_740884");
        for(var i=0;i<testPassword.length;i++){
            cCode = testPassword.charCodeAt(i);
            fireKeyEvent(testss, "keydown", cCode);
            fireKeyEvent(testss, "keypress", cCode);
            fireKeyEvent(testss, "keyup", cCode);
        }