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HTML Send button

HTML Button that I create
I wanted to know if there is something for an HTML button, simulate that the ENTER key was pressed. Since I need a button to send an automatic chat in which I am working. I was able to implement the button, although it still does not perform any action. The messages are sent by pressing the ENTER key, so I wanted to find a way to simulate that action. Thank you
var fncTxMessageKeydown = function (e) {
e = window.event || e;
var keyCode = (e.which) ? e.which : e.keyCode;
if (keyCode == 13 && !e.shiftKey) {
if (e.preventDefault) {
e.preventDefault();
} else {
e.returnValue = false;
}
var message = elements.txMessage.value.toString().trim();
if (message!=""){
if (gotUid==true) {
EngtChat.sendMessage(message);
elements.txMessage.value = "";
}
else{
//show initialization alert and reconnect socket
document.getElementsByClassName("engt-sheet-header-with-presence")[0].style.padding="7px";
socket.disconnect();
socket.connect();
}
}
return false;
}
};
if (elements.txMessage != undefined) {
elements.txMessage.onkeydown = fncTxMessageKeydown;

show javascript message to user using onbeforeunload event only for browser close event

As per the project requirement, on which I am working now, I need to show user a javascript alert only in the event of browser close using javascript. All other page events like url click, button click, F5 key press etc. are to be disregarded. I have tried with the following code but with no use.
var isPostBack = false;
$(function() {
// You would copy this for select and any other form elements I forgot about
$('input').live('click', function() { isPostBack = true; });
$('a').live('click', function() { isPostBack = true; });
document.onkeydown = function(e) { //attach to key down event to detect the F5 key
isPostBack = false;
if (!e) { //Firefox and Safari gets argument directly.
e = window.event;
}
var key = e.keyCode ? e.keyCode : e.which;
try {
if (key == 116) { //F5 Key detected
isPostBack = true;
}
}
catch (ex) { }
}
});
window.onbeforeunload = check;
function check() {
if (!isPostBack) {
// Do your unload code
isPostBack = false;
var strPath = window.location.pathname;
if (strPath.indexOf('CustomerPortal') >= 0) {
alert('Customer, you are leaving our page.');
}
else {
alert('User, you are leaving our page.');
}
return "Are you sure you want to exit this page?";
}
}
Please help to achieve my target requirement with your valuable comments and help.

Jquery capture tab + some key combination

How can I catch, for example, tab+t combination with jQuery? I've found a lot of examples with alt, shift and ctrl, since event object contains special flags in order to understand if, for example, alt was pressed. But there is not such thing for tab.

This should work. It's a bit convoluted and there is likely an easier way, but it works fine.
JSFiddle: https://jsfiddle.net/spybhhxc/
var tabdown = false;
var tdown = false;
$(document).keydown(function(e) {
if(e.which == 9) {
tabdown = true;
}
if(e.which === 84)
{
tdown = true;
}
if(tabdown && tdown)
{
//do your thing
}
});
$(document).keyup(function(e) {
if(e.which == 9) {
tabdown = false;
}
if(e.which === 84)
{
tdown = false;
}
});
This presents a problem though, as once you press tab, the document is unfocused as the tab key navigates to elements in a browser. You would be much better off using something like alt or ctrl which don't interact with the browser.

We can have a tab key pressed [tabPressed] variable which will be set to true on key down and unset the same on its key up event. We will using the tab key pressed[tabPressed] variable to check whether it is in pressed state during the other key press activities. The tab keycode is 9.
jsfiddle link http://jsfiddle.net/e3Lveyj2/
var tabPressed=false;
function handleKeyDown(e) {
var evt = (e==null ? event:e);
if(evt.keyCode == 9){
tabPressed=true;
}
if ((tabPressed) && (evt.keyCode == 84)) {
alert ("You pressed 'Tab+t'")
}
}
function handleKeyUp(e) {
var evt = (e==null ? event:e);
if(evt.keyCode == 9){
tabPressed=false;
}
}
document.onkeydown = handleKeyDown;
document.onkeyup = handleKeyUp;

javascript browser closing

i have an issue regarding browser closing detection.i my asp.net application when user closes browser abruptlly i need to call a logout service which update loginstatus from true to false,i am doing this as below
function Logout() {
var Userid = $("#hdnfuid").val();
var branch = $("#hdnfbranch").val();
var service = LogoutService.Logout(Userid + "," + branch, SucceededCallback);
//alert(service);
}
function SucceededCallback(result) {
}
var isClose = false; ;
//this code will handle the F5 or Ctrl+F5 key
//need to handle more cases like ctrl+R whose codes are not listed here
document.onkeydown = checkKeycode
function checkKeycode(e) {
var keycode;
if (window.event)
keycode = window.event.keyCode;
else if (e)
keycode = e.which;
if (keycode == 116) {
isClose = true;
}
}
function somefunction() {
isClose = true;
}
function doUnload() {
if (!isClose) {
var selection = confirm('window is closing');
if (selection == true)
{var x=confirm("closing browser");
if(x==true)Logout();
else
return false;}
else {
return false;
}
}
but the problem is that when i click cancle of confirm box in that case also browser closes.
i also need to call same service on session_end event of global.asax
please suggest me the way of doing this.
}
but the problem is that

Stuck alt / modifier key with Javascript

I have a library that creates an editor on the fly (http://epiceditor.com) and also sets up key shortcuts automatically. The shortcuts can be configured in the options so I can't use e.altKey, e.ctrlKey, etc just a heads up.
For some reason the modifier key isn't being set back to false sometimes on Mac/Ubuntu browsers.
On Windows it seems to happen every time. You can reproduce this by clicking render in JSBin then pressing alt+p. You should see "Yay" appear. Now, if on Windows press just p again. You'll see "Yay appear again. Mac and Ubuntu users have seen this same issue occasionally but it's hard to reproduce it.
Also note this only happens with the alt key it seems. Below I have 16 (shift) next to the 18 (alt). If you swap those out it'll work as expected.
The code for the stripped down test case is:
var modKey = false;
var modKeyCode = 18; //16
document.body.addEventListener('keydown', function (e) {
if (!modKey && modKeyCode == e.keyCode) {
modKey = true;
}
if (modKey && e.keyCode == 80) {
console.log('Yay!');
}
});
document.body.addEventListener('keyup', function (e) {
if (modKey && modKeyCode == e.keyCode) {
modKey = false;
}
});
Demo: http://jsbin.com/uhupah/3/edit#javascript,html

I do not have access to my Linux box at the moment, so i cannot test your code.
Thus here is more of a suggestion:
Linux (in my experience) is finicky when it it comes to keyCodes and order of key events. Perhaps combine the if(..) from keyup with that of keydown
if (!modKey && modKeyCode == e.keyCode) {
modKey = true;
} else if (modKey && modKeyCode == e.keyCode) {
modKey = false;
}
The above suggestion is made with assumption that you have no specific requirement to have both 'keydown' and 'keyup'.

I've come up with a fix, albeit a sort of crappy fix, but a fix nonetheless.
The fix I went with was to reset the modifier var when any key combo was successful. I.e. one the p in alt+p is pressed reset the modKey to false like this:
var modKey = false;
var modKeyCode = 18; //16
document.body.addEventListener('keydown', function (e) {
if (!modKey && modKeyCode == e.keyCode) {
modKey = true;
}
if (modKey && e.keyCode == 80) {
console.log('Yay!');
modKey = false; //THIS
}
});
document.body.addEventListener('keyup', function (e) {
if (modKey && modKeyCode == e.keyCode) {
modKey = false;
}
});
The problem with this tho is that you can't do back to back key commands. Most of the time this is alright because the user will do a key command like "save" or "preview" or something, type some more, then do another key command. But you wouldn't be able to, let's say: alt+p s to trigger alt+p then alt+s without having to let go of the alt key.