Develop Reference

How can I modify an anonymous javascript function with tampermonkey?

Here is the block of code I want to replace:
$(document).ready(function () {
$(".button-purple").click(function () {
interval = $(this).attr('id');
name = $(this.attr('name');
if(Number($(this).val()) === 0) {
if(name == 'static') {
do this
}
else {
do this
}
}
else {
do this
}
});
});
I can't find any documentation on trying to replace the function since it's unnamed though. Is it possible to replace the entire javascript file + delete the line loading it / insert my own script? Would really appreciate any help I can get.

If you just want to remove the click event handler, then simply say
var $element = $(".button-purple");
$element.off('click');
If you want to Remove all the event handlers, then you'll first have to find out what all event handlers are present and then remove them iteratively.
var element = $element[0]; //Make sure the element is a DOM object and not jQuery Object.
// Use this line if you're using jQuery 1.8+
var attachedEvents = $._data(element,'events');
// Use this line if you're using jQuery < 1.8
var attachedEvents = $(element).data('events'); //Here you can also replace $(element) with $element as declared above.
for(var event in attachedEvents){
$element.off(event);
}
UPDATE:
You can simply add your own event handler (using .on() API) after you're done removing all the required existing handlers.
Just define your function.
function yourFunction(){ /* your code */};
$element.on('click', yourFunction);
Update 2:
Since you just want to remove the click event handler, this is the simplest code that will serve your purpose.
$(".button-purple").off('click').on('click', yourFunction);

I'm not aware of tampermonkey, but you can try this:
function chickHandler() {
interval = $(this).attr('id');
name = $(this.attr('name');
if (Number($(this).val()) === 0) {
if (name == 'static') {
do this
} else {
do this
}
} else {
do this
}
}
}
function onReadyHandler() {
$(".button-purple").click(chickHandler);
}
$(document).ready(onReadyHandler);
When you do something like .click(function(){...}), here function is called as a callback. You have to send a function as a callback. Not necessary to be anonymous.

I want to click to implement the event once, then remove event from the element that clicked

As in the title of the question.
I have many elements, because I have used getElementsByTagName('*').
Then, I have added a click event on every element, and I have used loop for that.
See the code:
HTML
<div id="box">
<span class="box"> span</span><br/>
<span class="box">span 2</span><br/>
<span class="box">span 3</span><br/>
</div>
<div id="result"></div>
Javascript
var element = document.getElementsByTagName('*'),
len = element.length, result = document.getElementById('result'), i, timer;
for (i = 0; i < len; i++) {
element[i].addEventListener('click', fn = function (e) {
clearTimeout(timer);
result.style.display = 'inline';
result.innerHTML = "<pre>" + e.target.innerHTML + "</pre>";
timer = window.setTimeout(function () {
result.style.display = 'none';
}, '2000');
e.target.removeEventListener('click', fn);
});
}
I want to when a user clicks on a specific element, implement the
event once, then removes the event from this element only.
Also, I want to add the function(callback) name to the removeEventListener function automatically, not like this e.target.removeEventListener('click', fn) //fn is the callback name.

the event callback gets called with the context of element, you have added the listener to it, here this would point to element[i],so you can change it like:
element[i].addEventListener('click', function fn(e) {
//your stuff
this.removeEventListener('click', fn);
});
note that if you create fn function this way, it is kind of private in the function body, we used to use arguments.callee which is not a good practice these days, you can not use it in strict mode.
all I am saying is by the time strict mode showed up since:
The 5th edition of ECMAScript (ES5) forbids use of arguments.callee()
in strict mode.
we could do that like this:
element[i].addEventListener('click', function(e) {
//your stuff
this.removeEventListener('click', arguments.callee);
});
but the new alternative is using function's label, for instance if you do:
var myfunc = function func(){
//you have access to the current function using func
//and you can add or remove it to/from something
someThing.removeEventListener('click', func);
};
//but if you want to do it here you can have it using myfunc
someOtherThing.removeEventListener('click', myfunc);
So that's what I mean by:
kind of private in the function body
you have access to that function in the function body using its label func, but out there in the code you don't have it.

Define function before as a variable. http://jsfiddle.net/m8UgC/
var element = document.getElementsByTagName('*'),
len = element.length, result = document.getElementById('result'), i, timer;
var fn = function (e) {
clearTimeout(timer);
result.style.display = 'inline';
result.innerHTML = "<pre>" + e.target.innerHTML + "</pre>";
timer = window.setTimeout(function () {
result.style.display = 'none';
}, '2000');
this.removeEventListener('click', fn);
}
for (i = 0; i < len; i++) {
element[i].addEventListener('click', fn);
}

how to get javaScript event source element?

Is there a way to retrieve the element source of an inline javaScript call?
I have a button like this:
<button onclick="doSomething('param')" id="id_button">action</button>
Note:
the button is generated from server
I cannot modify the generation process
several buttons are generated on the page, I have control only on client side.
What I have tried:
function doSomething(param){
var source = event.target || event.srcElement;
console.log(source);
}
On firebug I get event is not defined
Edit:
After some answers, an override of the event handling using jQuery is very acceptable. My issue is how to call the original onClick function with it's original prameters, and without knowing the function name.
code:
<button onclick="doSomething('param')" id="id_button1">action1</button>
<button onclick="doAnotherSomething('param1', 'param2')" id="id_button1">action2</button>.
<button onclick="doDifferentThing()" id="id_button3">action3</button>
.
.
and so on..
So the override would be:
$(document).on('click', 'button', function(e) {
e.preventDefault();
var action = $(this).attr('onclick');
/**
* What to do here to call
* - doSomething(this, 'param'); if button1 is clicked
* - doAnotherSomething(this, 'param1', 'param2'); if button2 is clicked
* - doDifferentThing(this); if button3 is clicked
* there are many buttons with many functions..
*/
});

Your html should be like this:
<button onclick="doSomething" id="id_button">action</button>
And renaming your input-paramter to event like this
function doSomething(event){
var source = event.target || event.srcElement;
console.log(source);
}
would solve your problem.
As a side note, I'd suggest taking a look at jQuery and unobtrusive javascript

You should change the generated HTML to not use inline javascript, and use addEventListener instead.
If you can not in any way change the HTML, you could get the onclick attributes, the functions and arguments used, and "convert" it to unobtrusive javascript instead by removing the onclick handlers, and using event listeners.
We'd start by getting the values from the attributes
$('button').each(function(i, el) {
var funcs = [];
$(el).attr('onclick').split(';').map(function(item) {
var fn = item.split('(').shift(),
params = item.match(/\(([^)]+)\)/),
args;
if (params && params.length) {
args = params[1].split(',');
if (args && args.length) {
args = args.map(function(par) {
return par.trim().replace(/('")/g,"");
});
}
}
funcs.push([fn, args||[]]);
});
$(el).data('args', funcs); // store in jQuery's $.data
console.log( $(el).data('args') );
});
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<button onclick="doSomething('param')" id="id_button1">action1</button>
<button onclick="doAnotherSomething('param1', 'param2')" id="id_button1">action2</button>.
<button onclick="doDifferentThing()" id="id_button3">action3</button>
That gives us an array of all and any global methods called by the onclick attribute, and the arguments passed, so we can replicate it.
Then we'd just remove all the inline javascript handlers
$('button').removeAttr('onclick')
and attach our own handlers
$('button').on('click', function() {...}
Inside those handlers we'd get the stored original function calls and their arguments, and call them.
As we know any function called by inline javascript are global, we can call them with window[functionName].apply(this-value, argumentsArray), so
$('button').on('click', function() {
var element = this;
$.each(($(this).data('args') || []), function(_,fn) {
if (fn[0] in window) window[fn[0]].apply(element, fn[1]);
});
});
And inside that click handler we can add anything we want before or after the original functions are called.
A working example
$('button').each(function(i, el) {
var funcs = [];
$(el).attr('onclick').split(';').map(function(item) {
var fn = item.split('(').shift(),
params = item.match(/\(([^)]+)\)/),
args;
if (params && params.length) {
args = params[1].split(',');
if (args && args.length) {
args = args.map(function(par) {
return par.trim().replace(/('")/g,"");
});
}
}
funcs.push([fn, args||[]]);
});
$(el).data('args', funcs);
}).removeAttr('onclick').on('click', function() {
console.log('click handler for : ' + this.id);
var element = this;
$.each(($(this).data('args') || []), function(_,fn) {
if (fn[0] in window) window[fn[0]].apply(element, fn[1]);
});
console.log('after function call --------');
});
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<button onclick="doSomething('param');" id="id_button1">action1</button>
<button onclick="doAnotherSomething('param1', 'param2')" id="id_button2">action2</button>.
<button onclick="doDifferentThing()" id="id_button3">action3</button>
<script>
function doSomething(arg) { console.log('doSomething', arg) }
function doAnotherSomething(arg1, arg2) { console.log('doAnotherSomething', arg1, arg2) }
function doDifferentThing() { console.log('doDifferentThing','no arguments') }
</script>

Cross-Browser solution
I believe the solution by #slipset was correct, and it doesn't need jQuery, BUT it wasn't cross-browser ready.
According to Javascript.info, events (when referenced outside markup events) are cross-browser ready once you assure it's defined with this simple line: event = event || window.event.
So the complete cross-browser ready function would look like this:
function logMySource(param){
event = event || window.event;
var source = event.target || event.srcElement;
console.log("sourceID= "+source.id,"\nsourceTagName= "+source.tagName,"\nparam= "+param);
}
<button onclick="logMySource('myVariable')" id="myID">action</button>
Try it!
I've included returns of useful information of the source.

You can pass this when you call the function
<button onclick="doSomething('param',this)" id="id_button">action</button>
<script>
function doSomething(param,me){
var source = me
console.log(source);
}
</script>

Try something like this:
<html>
<body>
<script type="text/javascript">
function doSomething(event) {
var source = event.target || event.srcElement;
console.log(source);
alert('test');
if(window.event) {
// IE8 and earlier
// doSomething
} else if(e.which) {
// IE9/Firefox/Chrome/Opera/Safari
// doSomething
}
}
</script>
<button onclick="doSomething('param')" id="id_button">
action
</button>
</body>
</html>

USE .live()
$(selector).live(events, data, handler);
As of jQuery 1.7, the .live() method is deprecated. Use .on() to attach event handlers.
$(document).on(events, selector, data, handler);

Detecting Href Is Clicked

I'm trying to detect if certain element is clicked on onbeforeunload. I can't get it to work. Below is examples of the Javascript code and HTML code on the project (Please note that I have no control over the HTML element as it is not my site)
function checkLeave() {
var p = document.getElementByElementById('yeah');
if (p.href.onclick) {
//do something
}
else {
//do something else
}
}
window.onbeforeunload = checkLeave;
HTML CODE
//The goSomewhere goes to another page
<a id="yeah" href="javascript:goSomewhere();">
<img src="smiley.png">
</a>
Thanks in advance,
J

What you need to do is bind an event handler to each on the page.
This can be done with the following:
// Select all links
//var allLinks = document.querySelectorAll('a[href]');
var allLinks = document.links;
// Bind the event handler to each link individually
for (var i = 0, n = allLinks.length; i < n; i++) {
//allLinks[i].addEventListener('click', function (event) {});
allLinks[i].onclick = function () {
// Do something
};
}

You are testing for the presence of the onclick property to the <a> tag. It isn't present in the markup. Rather than using the onclick, the markup calls a script as the element's href. So you need to look for a script in the href instead:
var p = document.getElementByElementById('yeah');
if (p.href.indexOf("javascript") === 0) {
//do something
}
else {
// do something else
}

Maybe something like this? (just the idea)
document.getElementById('yeah').onclick = function() {
clicked = this.href;
};

Is there a way to get all event-listener bindings in Javascript?

I am searching for a way where I can list all event-listener bindings that are made with JS (or other scripts as well) on a website. Mainly I want to find out double bindings (for debug reason), but I guess there are other issues for it as well.
Brilliant would be a plugin for the browser, where you can see on the website which elements have which kinds of eventlisteners bound. You know, some visualization of the event-listeners...

Visual Event (http://www.sprymedia.co.uk/article/Visual+Event+2) is very helpful. Go to this page and just drag the "Visual Event" link into your bookmark bar. When you want to check a page, just click it, wait a second, and the events for each element will be overlaid on the page.

There's only one type of event declaration that you get it, I don't know if this will help you:
// Can't get
myDiv.attachEvent ("onclick", function () {alert (1)});
// Can't get
myDiv.addEventListener ("click", function () {alert (1)}, false);
// Can't get
<div onclick = "alert (1)"></div>
// Can get
myDiv.onclick = function () {alert (1)}
You may look this answer too. Anyway I made a function for you:
<!DOCTYPE html>
<html>
<head>
<script>
function getAllEvents () {
var all = document.getElementsByTagName ("*");
var _return = "";
for (var i = 0; i < all.length; i ++) {
for (var ii in all[i]) {
if (typeof all[i][ii] === "function" && /^on.+/.test (ii)) { // Unreliable
_return += all[i].nodeName + " -> " + ii + "\n";
}
}
}
return _return;
}
document.addEventListener ("DOMContentLoaded", function () {
var div = this.getElementsByTagName ("div")[0];
div.onclick = function () {
alert (1);
}
div.onmouseout = function () {
alert (2);
}
alert (getAllEvents ());
}, false);
</script>
<style>
div {
border: 1px solid black;
padding: 10px;
}
</style>
</head>
<body>
<div></div>
</body>
</html>

I just wrote a script that lets you achieve this. It gives you two global functions: hasEvent(Node elm, String event) and getEvents(Node elm) which you can utilize. Be aware that it modifies the EventTarget prototype method add/RemoveEventListener, and does not work for events added through HTML markup or javascript syntax of elm.on_event = ..., works only for add/RemoveEventListener.
More info at GitHub
Live Demo
Script:
var hasEvent,getEvents;!function(){function b(a,b,c){c?a.dataset.events+=","+b:a.dataset.events=a.dataset.events.replace(new RegExp(b),"")}function c(a,c){var d=EventTarget.prototype[a+"EventListener"];return function(a,e,f,g,h){this.dataset.events||(this.dataset.events="");var i=hasEvent(this,a);return c&&i||!c&&!i?(h&&h(),!1):(d.call(this,a,e,f),b(this,a,c),g&&g(),!0)}}hasEvent=function(a,b){var c=a.dataset.events;return c?new RegExp(b).test(c):!1},getEvents=function(a){return a.dataset.events.replace(/(^,+)|(,+$)/g,"").split(",").filter(function(a){return""!==a})},EventTarget.prototype.addEventListener=c("add",!0),EventTarget.prototype.removeEventListener=c("remove",!1)}();