Develop Reference

Issue in getting device Contact Number

I am trying to get the mobile device contact number using Cordova Phonegap application . While I was searching in google I got this URL LINK which is the exact one that I required .I followed every step of the post and following to which i wrote this snippet to get the device phone number..
var telephoneNumber = cordova.require("cordova/plugin/telephonenumber");
telephoneNumber.get(function(result) {
console.log("result = " + result);
alert('result : '+result);
}, function(error) {
console.log("error = " + error.code);
alert('Error: '+error);
});
I have put alert inside the error function to see the error message .Now i am trying to execute this on the mobile device but not getting any alert message too.In the above snippet i am missing one line to understand i.e
var telephoneNumber = cordova.require("cordova/plugin/telephonenumber");
In the above line i am not getting what is this cordova/plugin/telephonenumber .Is this some refrence file because i have no directory available with me like this ..Do i need to create a folder by name Cordova and plugin and put telephonenumber.js file inside to it..
Please help me with this ..Thanks..

ContextMenu.add shows a warning whenever initiated

I'm trying to follow sample for appAPI.contextMenu in Crossrider API
http://docs.crossrider.com/#!/api/appAPI.contextMenu-method-add
background.js
appAPI.ready(function() {
// Adds a command to all context menus that displays the data object
appAPI.contextMenu.add("key1", "Display data object", function (data) {
console.log('pageUrl: ' + data.pageUrl + '\n' +
'linkUrl: ' + data.linkUrl + '\n' +
'selectedText:' + data.selectedText + '\n' +
'srcUrl:' + data.srcUrl);
}, ["all"]);
// Adds a command to "link" context menus that displays 'Hello World'
// Note: Since both commands display on links, they are grouped in a sub menu
appAPI.contextMenu.add("key2", "Hello World", function (data) {
console.log('Changed onClick to Alert Hello World');
}, ["link"]);
});
extension.js
appAPI.ready(function($) {
});
the following warn is thrown in console log of background page.
Warning: Parameter context value is not supported. Function-name:
appAPI.contextMenu.add
PS, if you are a Crossrider Staff willing to help, a sample can be reproduced by extension id: 62139

The message is a mere warning and does not affect the operation of the extension; hence, it can be safely ignored.
I took the additional precaution of installing the extension on Chrome and Firefox and the context menu works correctly as defined in your code. If you have a specific issue with the extension not working correctly, please feel free to email support#crossrider.com.
[Disclaimer: I am a Crossrider employee]

wkhtmltopdf and the jQuery.ready() function

I've been trying to generate a PDF using the wkhtmltopdf tool (http://wkhtmltopdf.org/). The page from which I want to generate a PDF using jQuery and has some initializations using a jQuery.ready() function, something like this:
jQuery(function() {
// do something
});
However, when I try to generate a PDF from the page the script is not executed. I've tried setting a delay to wait for the JavaScript to be executed with the option:
--javascript-delay 30000
But the result is the same.
When I've enabled wkhtmltopdf's JavaScript debugging option I get a warning, which I'm not sure if it's related to the problem:
Warning: undefined:0 TypeError: 'null' is not an object
Has anyone encountered this problem? Is there some kind of workaround?
EDIT: Seems the problem is caused by the error Warning: undefined:0 TypeError: 'null' is not an object. I've managed to print the error on the PDF using:
window.onerror = function(error, url, line) {
$('body').before('<b> Error: ' + error + '</b> <br />');
$('body').before('<b> Url: ' + url + '</b> <br />');
$('body').before('<b> Line: ' + line + '</b> <br />');
console.log(error, ' ', url, ' ', line);
};
But the information is very limited and I have no idea what might cause it:
Error: TypeError: 'null' is not an object
Url: undefined
Line: 0

The problem turned out to be that Qt doesn't support localStorage, so one of the initialization scripts failed which cause the jQuery.ready() not being executed.
I've managed to debug it with a browser with Qt support: QtWeb. (Tried Arora as well, couldn't run it on my system).

Is there a way to try/catch an entire page dynamically?

I have a page on which mysterious JavaScript errors keep popping up. They appear to be coming from the application we use and do not own the source for. I'm working on a real solution to this issue, but we have a demo tomorrow and I was wondering if there is a way to just suppress JS errors page wide (like wrapping ALL the javascript components in a giant try catch).

You could add a handler to the window.onerror event. In this case, all the errors that occur inside the window will be redirected to the handler of this event. (I did test this in Firefox and it worked, but I was having trouble with it in Chrome - my Chrome installation is pretty messed up, so that could be the problem, but there are Chromium bugs filed that relate to this issue: bug #7771 and bug #8939)
window.onerror = function (msg, url, line) {
alert("Error on line " + line + " in " + url + ":\n" + msg);
// return true to prevent browser from displaying error
return true;
}

Does Javascript fire an event for unhandled/uncaught exceptions?

I'm looking to log unhandled javascript exceptions. Is there an event that fires when an exception isn't caught? I'm looking to catch the exceptions before they cause javascript errors in the browser, but I'd rather not run my entire application inside of a try/catch. Any help would be appreciated. Thanks!
Update:
tvanfosson pointed out onerror as a possibility. It is not part of a spec and is only available in IE or Gecko based browsers.
For more information - http://books.google.com/books?id=tKszhx-XkzYC&pg=PA386&lpg=PA386&dq=safari+onerror+javascript&source=web&ots=gQaGbpUnjG&sig=iBCtOQs0aH_EAzSbWlGa9v5flyo#PPA387,M1
OnError Support Table - http://www.quirksmode.org/dom/events/error.html
Mozilla's documentation - https://developer.mozilla.org/en/DOM/window.onerror
WebKit Bug Report - https://bugs.webkit.org/show_bug.cgi?id=8519

Check out this Fiddle:
http://jsfiddle.net/xYsRA/1/
window.onerror = function (msg, url, line) {
console.log("Caught[via window.onerror]: '" + msg + "' from " + url + ":" + line);
return true; // same as preventDefault
};
window.addEventListener('error', function (evt) {
console.log("Caught[via 'error' event]: '" + evt.message + "' from " + evt.filename + ":" + evt.lineno);
console.log(evt); // has srcElement / target / etc
evt.preventDefault();
});
throw new Error("Hewwo world. I crash you!!!");
throw new Error("Hewwo world. I can only crash you once... :(");
Which prints:
Caught[via window.onerror]: 'Uncaught Error: Hewwo world. I crash you!!!' from http://fiddle.jshell.net/xYsRA/1/show/:32 fiddle.jshell.net:21
Caught[via 'error' event]: 'Uncaught Error: Hewwo world. I crash you!!!' from http://fiddle.jshell.net/xYsRA/1/show/:32 fiddle.jshell.net:26
ErrorEvent {lineno: 32, filename: "http://fiddle.jshell.net/xYsRA/1/show/", message: "Uncaught Error: Hewwo world. I crash you!!!", clipboardData: undefined, cancelBubble: false…}
fiddle.jshell.net:27\
Notes:
If you remove the "return true" / "evt.preventDefault()" lines, then after the error is logged, it will print on the JS console in the normal way.
Contrary to statements made above, window.onerror worked in all the browsers I tested. However, the addEventListener method is probably better anyways and provides richer semantics.

Try using an onerror handler. Docs from MDN. This will allow you to do something when an error is detected, but probably won't let you continue in a graceful way that a try/catch block would. Be aware that are undoubtedly differences between browsers in how this is handled.