Back Button intercepted for ever - Phonegap/Android - javascript

In my Android phonegap/Cordova 3.5 project, I have 3 html pages (a button in index.html calls page2.html where there is another button calling page3.html).
In page2.html I override backbutton doing this in deviceReady:
document.addEventListener("backbutton", onBackKeyDown, false);
then
function onBackKeyDown() {
console.log("onBackKeyDown");
navigator.app.exitApp();
}
but in page3.html I want to let Android controlling backbutton so I do not override it in page3.html.
Instead in page3.html backbutton is disabled.
Questions:
Is this the expected behaviour (overriding one means overriding for
ever)?
How to get rid with this? (leave the control of backbutton to
Android anytime I want to)

You can check the page in the OnBackKeyDown event:
function onBackKeyDown() {
var pagename = // get the page name here
if ( pagename == page3.html ) {
history.back();
}
else {
navigator.app.exitApp();
}
}

You can back button behaviour according to each page. Example is shown below.
function onBackKeyDown(e) {
if ($.mobile.activePage[0].id == "home"
|| $.mobile.activePage[0].id == "login") {
e.preventDefault();
navigator.app.exitApp();
}else if($.mobile.activePage[0].id == "inspection"){
e.preventDefault();
back();
//return false;
}else if($.mobile.activePage[0].id == "noDetails"){
e.preventDefault();
$.mobile.changePage("home.html");
return false;
}else{
navigator.app.backHistory();
}
}
I am using jQuery Mobile- gives more control over page transitions.

the real solution to this question is probably to remove the event with this API:
document.removeEventListener("backbutton", onBackKeyDown, false);
I found it here

Related

prevent link click event except open in new window hotkey is pressed

So I have my website, a website without reload between site switches.
For SEO reasons, my links look like this:
View more
<script>
// code is strongly simplified, for more clarity
document.getElementById("viewmore").addEventListener("click",function(e) {
e.preventDefault();
myHandler.goTo(e.currentTarget.href);
});
</script>
myHandler is the site handler in this case.
If I click the hotkey for opening a link in a new tab (on Mac it is CMD+Click), it does not work, as the event is prevented.
How to check if the link should open in a new tab or not? (Check if the hotkey is pressed or not)
Not sure I understood it, but try this
document.getElementById("viewmore").addEventListener("click", (e) => {
// ctrlKey / altKey / shiftKey
if (e.ctrlKey) myHandler.goTo(e.currentTarget.href);
else e.preventDefault();
});
You can store the state of the CMD key in a variable and check it when the link is clicked.
let isCmdPressed = false;
document.addEventListener("keydown",(e)=>{
if (e.key == "Meta"){
isCmdPressed = true;
}
});
document.addEventListener("keyup",(e)=>{
if (e.key == "Meta"){
isCmdPressed = false;
}
});
document.getElementById("viewmore").addEventListener("click",function(e) {
if (!isCmdPressed){
e.preventDefault();
myHandler.goTo(e.currentTarget.href);
}
});

keyboard shortcut using javascript not working

I am using command + h as a shortcut key in my website. It is not doing the function to be done. After I click something on the window only it works flawlessly. Here is my code..
window.onkeydown = function(event) {
if (event.keyCode == 72 && (event.metaKey == true)) {
//some function
}
}
Somebody try to rectify . I have included this code only after the dom gets loaded
window.onkeydown will only work if it is focused. So on body load you should set focus.
<body onload="setFocus()">
function setFocus(){
window.focus();
}
Working DEMO HERE
You could probably make it work with focusing the body on window load with document.body.focus() and attaching an event listener like this:
window.onload = function() {
document.body.focus();
document.addEventListener("keydown", keyDownFunction, false);
};
function keyDownFunction(event) {
if(event.keyCode == 72 && (event.metaKey == true)) {
alert("You hit the right keys.");
}
}

External Link Notification - JavaScript or JQuery

I am looking for a way to set it up so that when an external link is clicked it will warn people that they are leaving the site. Preferably, it would darken the screen and display a message in the middle of the screen in a box with the option to click OK or Cancel.
I tried to use this code:
$("a.external").click(function () {
alert("You are about to proceed to an external website. The Great Western Market has no control over the content of this site. Click OK to proceed.");
});
and give each link a class of external but it doesn't seem to work. I don't want to use this because it means that the client will have to remember to add the class I would prefer something more automatic.
I also tried to use this code to do so but to no avail:
$('a').filter(function() {
return this.hostname && this.hostname !== location.hostname;
})
.click(function () {
var x=window.confirm('You are about to proceed to an external website. The Great Western Market has no control over the content of this site. Click OK to proceed.');
var val = false;
if (x)
val = true;
else
val = false;
return val;
});
I am using WordPress 3.8.1.
Thanks in advance for any help you can give.
Your filter logic should be correct, Try using the confirm function, and using jQuery instead of $.
jQuery('a').filter(function() {
return this.hostname && this.hostname !== location.hostname;
}).click(function(e) {
if(!confirm("You are about to proceed to an external website."))
{
// if user clicks 'no' then dont proceed to link.
e.preventDefault();
};
});
I tried this out in dev tools on your site and it seems to work correctly if you use jQuery. I think you may have some plugin that is causing conflicts with $.
JSFiddle Demo
Try using confirm instead of alert since that will pause and wait for user input. You'll then need function(e){ e.preventDefault(); } to prevent the default link actions.
To identify just external links you might do something like this:
var ignoreClick = false;
$(document).ready( function(){
$('input[type="submit"], input[type="image"], input[type="button"], button').click(function(e) {
ignoreClick = true;
});
$(document).click(function(e) {
if($(e.target).is('a'))
checkLink(e);
});
$('a').click(function(e) {
checkLink(e);
return true;
});
checkLink = function(e){
// bubble click up to anchor tag
tempTarget = e.target;
while (!$(tempTarget).is('a') && !!tempTarget.parentElement) {
tempTarget = tempTarget.parentElement;
}
if ($(tempTarget).is('a')){
if(!!tempTarget && $(tempTarget).is('a') &&
(tempTarget.hostname == "" || tempTarget.hostname == "#" || tempTarget.hostname == location.hostname)){
ignoreClick = true;
}
}
}
});
and to catch people with a message you might use beforeunload and the confirm option
$(window).bind("beforeunload", function (e) {
if (!ignoreClick){
if(!confirm("Leaving website message")) {
e.preventDefault();
}
}
});
It worked pretty well to me. I just removed unnecesary variables, but original script worked fine.
$('a').filter(function() {
return this.hostname && this.hostname !== location.hostname;
})
.click(function () {
return window.confirm('You are about to proceed to an external website. The Great Western Market has no control over the content of this site. Click OK to proceed.');
});
http://jsfiddle.net/3dkAN/1/
EDIT
Following #user1308743's line, seems that in cgmp.framework.min.js is summoning the jQuery.noConflict() mode, that unbinds the $() function for jQuery. So please use jQuery() for any jQuery implementation

Hide submit button after server validation

I have found this online:
function submitButtonClick(button) {
if (typeof (Page_ClientValidate) == 'function') {
if (Page_ClientValidate() == false) {
return false;
}
}
button.style.display = 'none'; // disable won't work
return true;
}
I am not good with Javascript so I couldn't tell what to change...I have a usercontrol with a few buttons, including a submit button. And they are used on every page of my site. And on some pages I have customvalidators. So when a custom validator doesn't validate, the button is gone and there is nothing left to do. What should I change here for the things to work the way I need? Thanks

DropDownList not firing onbeforeunload when AutoPostBack="True"

I have implemented an "unsaved changes" warning using techniques described on these pages:
Client/JS Framework for "Unsaved Data" Protection?
http://kenbrowning.blogspot.com/2009/01/using-jquery-to-standardize.html
This works well except for a DropDownList on the page. It does an AutoPostBack, and I want onbeforeunload to fire because unsaved changes will be lost, but it isn't working. Should it be raising the onbeforeunload event? Can I somehow make it raise the event?
Edit:
The DropDownList is inside an UpdatePanel, so that means it isn't unloading the page and that would be why onbeforeunload isn't being triggered. Is there any way I can trigger the event programmatically? Or do I have to roll my own imitation Confirm dialog?
Edit2
I now have a solution that adds the dialog to asynchronous postbacks from an UpdatePanel. I have edited the original script, adding the call to setConfirmAsyncPostBack() as described in my solution.
Here is my JavaScript:
/****Scripts to warn user of unsaved changes****/
//https://stackoverflow.com/questions/140460
//http://jonstjohn.com/node/23
//Activates the confirm message onbeforeunload.
function setConfirmUnload(on) {
setConfirmAsyncPostBack();
if (on) {
removeCheckFromNoWarnClasses();
fixIEonBeforeUnload();
window.onbeforeunload = unloadMessage
return;
}
window.onbeforeunload = null
}
function unloadMessage() {
return 'You have unsaved changes.';
}
//Moves javascript from href to onclick to prevent IE raising onbeforeunload unecessarily
//http://kenbrowning.blogspot.com/2009/01/using-jquery-to-standardize.html
function fixIEonBeforeUnload() {
if (!$.browser.msie)
return;
$('a').filter(function() {
return (/^javascript\:/i).test($(this).attr('href'));
}).each(function() {
var hrefscript = $(this).attr('href');
hrefscript = hrefscript.substr(11);
$(this).data('hrefscript', hrefscript);
}).click(function() {
var hrefscript = $(this).data('hrefscript');
eval(hrefscript);
return false;
}).attr('href', '#');
}
//Removes warnings from Save buttons, links, etc, that have been can be given "no-warn" or "no-warn-validate" css class
//"no-warn-validate" inputs/links will only remove warning after successful validation
//use the no-warn-validate class on buttons/links that cause validation.
//use the no-warn class on controls that have CausesValidation=false (e.g. a "Save as Draft" button).
function removeCheckFromNoWarnClasses() {
$('.no-warn-validate').click(function() {
if (Page_ClientValidate == null || Page_ClientValidate()) {
setConfirmUnload(false);
}
});
$('.no-warn').click(function() {
setConfirmUnload(false);
});
}
//Adds client side events to all input controls to switch on confirmation onbeforeunload
function enableUnsavedChangesWarning() {
$(':input').one('change', function() {
window.onbeforeunload = function() {
return 'You have unsaved changes.';
}
});
removeCheckFromNoWarnClasses();
}
And in my ASP.NET page, when the user makes a change:
if (changed)
{
...
//Confirm unload if there are unsaved changes.
//NB we also have to call fixIEonBeforeUnload() to fix links, done in in page load to include links that are rendered during callbacks
ScriptManager.RegisterStartupScript(Page, GetType(), "unsavedchanges", "setConfirmUnload(true);", true);
}
else
...
Also see How to prevent AutoPostBack when DropDownlist is selected using jQuery
//http://msdn.microsoft.com/en-us/magazine/cc163413.aspx
//https://stackoverflow.com/questions/2424327/prevent-asp-net-dopostback-from-jquery-submit-within-updatepanel
//Adds an event handler to confirm unsaved changes when an asynchronous postback is initialised by an UpdatePanel
function setConfirmAsyncPostBack() {
if (typeof (Sys.WebForms) === "undefined" || typeof (Sys.WebForms.PageRequestManager) === "undefined")
return;
var prm = Sys.WebForms.PageRequestManager.getInstance();
prm.add_initializeRequest(confirmAsyncPostBack);
}
//An event handler for asynchronous postbacks that confirms unsaved changes, cancelling the postback if they are not confirmed
//Adds the confirmation to elements that have a css class of "warn"
function confirmAsyncPostBack(sender, args) {
if (window.onbeforeunload != null && args.get_postBackElement().className == "warn" && !unloadConfirmed())
args.set_cancel(true);
}
//Displays a confirmation dialog that imitates the dialog displayed by onbeforeunload
function unloadConfirmed() {
var confirmed = confirm("Are you sure you want to navigate away from this page?\n\n" + unloadMessage() + "\n\nPress OK to continue or Cancel to stay on the current page.");
if (confirmed)
window.onbeforeunload = null;
return confirmed;
}

Categories