Develop Reference

JavaScript and JQuery - Shift + Enter for a new line

I have a page wherein a user can click a button to post something. This works in a similar fashion as facebook.
When the user presses enter, the post will automatically be saved and displayed. When the user presses shift and enter, I was expecting a new line but it doesn't seem to work. I am using JQuery for that function. What could be wrong with this code ? I saw this solution while researching.
$("#someTextArea").keypress(function(event){
if(event.which == 13 && !event.shiftkey) {
// ajax
}
});

Try using event.keyCode and event.shiftKey(capital K [camel-case]);
For your task something like this should do:
var Keys = {
ENTER: 13
};
$("#someTextArea").keypress(function (event) {
if (event.keyCode == Keys.ENTER) {
if (event.shiftKey) {
// make a new line
} else {
//submit the text
}
}
});

Disable browsers' back button, completely

Need to prevent users going to the previous page, completely.
When I use the following code it works but it's not what I need exactly. When pressing the back button it says "Document Expired":
Response.Cache.SetExpires(DateTime.UtcNow.AddDays(-1));
Response.Cache.SetValidUntilExpires(false);
Response.Cache.SetRevalidation(HttpCacheRevalidation.AllCaches);
Response.Cache.SetCacheability(HttpCacheability.NoCache);
Response.Cache.SetNoStore();
Another idea - to open a new window without toolbar:
<script>
function PopupWithoutToolbar(link) {
var w = window.open(link.href,
link.target || "_blank",
'menubar=no,toolbar=no,location=no,directories=no,status=no,scrollbars=no,resizable=no,dependent,width=800,height=620,left=0,top=0');
return w ? false : true;
}
</script>
yahoo
But, still... If the user presses the backspace button on a keyboard he can go back. It seems that this approach is only for hiding and not disabling buttons.
Is there any way to simply ignore the back button?

I am not entirely sure if this will work, but you can try handling the event with javascript.
Like if you want to entirely disable the backspace button from allowing users to go back you can do like
$(window).on("keypress", function (e){
if(e.keycode == "backspace")
e.preventDefault();
})
I could figure out the keycode for backspace for you , but that isn't too hard to figure out. Also this uses jquery, but you can use just raw javascript. just wasn't sure what it would be offhand.

I'm using a slightly different solution:
history.pushState(null, null, location.href);
window.onpopstate = function () {
history.go(1);
}

Based on your post it sounds like your only issue is disabling the backspace button from allowing the user to go back.
Here's what I do for that using jquery. Still allows backspace to work inside enabled text editing inputs, where it should.
// Prevent the backspace key from navigating back.
$(document).unbind('keydown').bind('keydown', function (event) {
var doPrevent = false;
if (event.keyCode === 8) {
var d = event.srcElement || event.target;
if ((d.tagName.toUpperCase() === 'INPUT' && (d.type.toUpperCase() === 'TEXT' ||
d.type.toUpperCase() === 'PASSWORD' ||
d.type.toUpperCase() === 'FILE')) ||
d.tagName.toUpperCase() === 'TEXTAREA') {
doPrevent = d.readOnly || d.disabled;
}
else {
doPrevent = true;
}
}
if (doPrevent) {
event.preventDefault();
}
});

Simplest thing ever:
window.onhashchange = function (event) {
//blah blah blah
event.preventDefault();
return false;
}
You can handle the location domain etc from that (window.location) then cancel the event if you want in this case.
How to Detect Browser Back Button event - Cross Browser

To disable the back button in the browser you can use use the following code in your JavaScript on the page on which you want to disable the back button.
<script>
history.pushState(null, null, location.href);
window.onpopstate = function () {
history.go(1);
};
</script>

Use a preventdefault to get out of the loop after pressing Enter key

This is a complete revision of my initial question, all unnecessary resources and references were deleted
I am tying the same event listener to 2 different elements: a button and Enter key, and it looks like the following:
var funcelement = function(){
//function code
};
$('#buttonID').click(funcelement);
$('#inputID').keyup(function () {
if (event.which == 13) {
$('#buttonID').trigger('click');
}
})
What I am trying to do is to prevent propagation of the enter key press if focus is on the submit button(#buttonID) by using preventDefault().
So I tried various combinations to make it work. The following is the latest result on my attempts
$('#inputID').keyup(function () {
var hasfocus = $('#buttonID').is(':focus') || false;
if (event.which == 13) {
if (!hasfocus) {
event.preventDefault();
$('#buttonID').trigger('click');
//hasfocus = true;
}
else {
//event.preventDefault();
//$('#buttonID').trigger('click');
}
}
})
After I enter a text into an input box and press Enter key, a confirmation window with yes/cancel buttons pops up with focus on yes button. Once I press Enter again, another window confirming that changes were made pops up with Ok button focused on it. Once I press Enter again, everything I need is being made.
However, there is one problem: after the last step is done, I am going back to the if (!hasfocus) line.
How do I prevent that from happening? Once the stuff I need is done - I don't want to go into that line again.

You can pass a parameter to into the function and stop the propagation there like so:
var funcelement = function(event, wasTriggeredByEnterKey){
if (wasTriggeredByEnterKey && $('#buttonID').is(':focus')) {
event.stopPropagation;
}
//function code
};
$('#buttonID').click(funcelement);
$('#inputID').keyup(function () {
if (event.which == 13) {
$('#buttonID').trigger('click', [true]);
}
}
)
UPDATE
In order to answer your revised issue, you should use the "keydown" event rather than "keyup" when working with alerts. This is because alerts close with the "keydown" event but then you are still triggering the "keyup" event when you release the enter key. Simply change the one word like this:
$('#inputID').keydown(function () {
var hasfocus = $('#buttonID').is(':focus') || false;
if (event.which == 13) {
if (!hasfocus) {
event.preventDefault();
$('#buttonID').trigger('click');
//hasfocus = true;
}
else {
//event.preventDefault();
//$('#buttonID').trigger('click');
}
}
})

Button automatically enables/disables when input is changed

I want to disable/enable a button based on one input. It's simple, if the input is "", disable the button, otherwise, enable it.
$('#searchBarTextbox').on('change', function () {
if ($('#searchBarTextbox').val() !== "") {
$('#btnSearchOk').prop('disabled', false);
} else {
$('#btnSearchOk').prop('disabled', true);
}
});
This works ok, but it enables/disables the button only after the user has clicked outside the text box. Is it possible to have button disable/enable while user is writing in the text box not having them move outside. Can I bind on keyup event maybe ?

Try using input event for doing this,
$('#searchBarTextbox').on('input', function () {
$('#btnSearchOk').prop('disabled', $.trim($('#searchBarTextbox').val()) === "");
});

Try using keyup instead of change
Live demo
$('#searchBarTextbox').keyup(function () {
if ($('#searchBarTextbox').val() !== "") {
$('#btnSearchOk').prop('disabled', false);
} else {
$('#btnSearchOk').prop('disabled', true);
}
});

Phonegap - Determine exact element active

I need to change the back button functionality of my phonegap project, which I've succeeded in doing without any problem. The only issue now, is that I need to further change the functionality based on if the user has a certain field selected.
Basically, if the user has clicked in a field with the id of "date-selector1", I need to completely disable the back button.
I was attempting to use document.activeElement, but it only returns the type of the element (input in this case), but I still want the functionality to work when they are in a general input, but not when they are in an input of a specific id.
EDIT
I tried all of the suggestions below, and have ended up with the following code, but still no success.
function pluginDeviceReady() {
document.addEventListener("backbutton", onBackKeyDown, false);
}
function onBackKeyDown() {
var sElement = document.activeElement;
var isBadElement = false;
var eList = ['procedure-date', 'immunization-date', 'lab-test-done', 'condition-onset', 'condition-resolution', 'medication-start-date', 'medication-stop-date', 'reaction-date'];
console.log("[[ACTIVE ELEMENT: --> " + document.activeElement + "]]");
for (var i = 0;i < eList.length - 1;i++) {
if (sElement == $(eList[i])[0]) {
isBadElement = true;
}
}
if (isBadElement) {
console.log('Back button not allowed here');
} else if ($.mobile.activePage.is('#main') || $.mobile.activePage.is('#family') || $.mobile.activePage.is('#login')) {
navigator.app.exitApp();
} else {
navigator.app.backHistory();
}
}

if you're listening for the back button you can add this if statement:
if (document.activeElement == $("#date-selector1")[0]) {
/*disable button here, return false etc...*/
}
or even better (Thanks to Jonathan Sampson)
if (document.activeElement.id === "date-selector1") {
/*disable button here, return false etc...*/
}

You can have a flag set when a user clicks on a field or you can have a click event (or any other type of event) when a user clicks on the field that should disable the back button.
From the documentation it looks like for the specific page that the backbuton is conditional on you can drop back-btn=true removing that back button.
http://jquerymobile.com/test/docs/toolbars/docs-headers.html
If you need complex conditional functionality you can just create your own button in the header or footer, style it using jquery-mobile widgets and implement your own click functionality.