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Why event listener persists after manual removal

All,
I try to build a resizer UI like this:
My code is like:
<span class="grabber" draggable="false" #mousedown="grab"></span>
grab: function(e) {
var initX = e.screenX;
var mousemove = function(e) {
var offset = e.screenX - initX
initX = e.screenX;
}
var cancel = function(e) {
$(document).off("mousemove")
$(document).off("mouseup")
}
$(document).on("mousemove", mousemove)
$(document).on("mouseup", cancel)
mousemove = null;
cancel = null;
}
Basic idea is: I attach that grab event handler to mousedown, inside which I listen to mousemove until mouseup, then I remove those two event handlers from document.
I am pretty new to Chrome Performance tool, so I just simply record some drag of that resizer, then mouseup and drag again.
The result is confused, especially the number of listener goes up like crazy(but there seems no memory leak). I wonder where did I do wrong?

So what is happening here:
<span class="grabber" draggable="false" #mousedown="grab"></span>
every time mousedown happens vue runs grab
The safer thing to do in this case is attach the events directly to e.target also setting your handler function to null in the cancel function.
grab: function(e) {
var initX = e.screenX;
var target = e.target;
var mousemove = function(e) {
var offset = e.screenX - initX
initX = e.screenX;
}
var cancel = function(e) {
$(target).off("mousemove")
$(target).off("mouseup")
mousemove = null;
cancel = null;
}
$(target).on("mousemove", mousemove)
$(target).on("mouseup", cancel)
}

Use a flag variable instead of adding and removing the handler.
var mouseIsDown = false;
$(document).on("mousedown", function() {
mouseIsDown = true;
});
$(document).on("mouseup", function() {
mouseIsDown = false;
})
$(document).on("mousemove", function() {
if (mouseIsDown) {
// do what you want
}
});
The mousedown handler could be attached to specific elements that you can grab, rather than document.

change variable value after click jquery

I want to be able to click on a canvas, move it to the map, drop it on the map. After dropping it on the map, they can select the canvas on the map and move it again. The process is repeated. I have trouble with the ignoreMouseMove variable, it does not reset to false and is always true.
Here is link to the demo: https://pokemon-map-electro2k.c9users.io/index.html
var moveCanvas = function ($canvas, e) {
$(".map ul li." + $canvas).offset({
left: e.pageX - 30,
top: e.pageY - 30
});
};
// When user first click on canvas
var onmousemove = function ($canvas) {
var ignoreMouseMove = false;
// Make canvas follow cursor in the map area
$(".map").mousemove(function (e) {
if (ignoreMouseMove) return; // event handling mousemove is "disabled"
moveCanvas($canvas, e);
}).click(function () {
// "re-enable" mousemove
ignoreMouseMove = true;
// When canvas is click on again within the map area, make canvas follow cursor
$(".map ul li").click(function () {
$(".map").mousemove(function (e) {
if (!ignoreMouseMove) return;
moveCanvas($canvas, e);
}).click(function () {
// Click function does not work anymore. ignoreMouseMove can't be reset. It is always true
ignoreMouseMove = false;
})
});
});
};

You may need to change the below line
// "re-enable" mousemove
ignoreMouseMove = true;
in to
// "re-enable" mousemove
ignoreMouseMove = !ignoreMouseMove;

Removing event listeners before leaving a page

I've developed a javascript drag and drop that mostly uses the standard 'allowdrop', 'drag' and 'drop' events.
I wanted to customise the 'ghosted' dragged object, so I've added a display:none div that get populated with the innerHTML of the draggable element and made visible (display:block;) when the user starts dragging.
The draggable div is absolutely positioned and matches the mouse movements. For this I needed to add 3 event listeners to document.body. They are as follows:
document.body.addEventListener('dragover', function (ev) {
console.log("dragover event triggered");
ev = ev || window.event;
ev.preventDefault();
dragX = ev.pageX;
dragY = ev.pageY;
document.getElementById("dragged-container").style.left = (dragX - dragOffsetX) + "px";
document.getElementById("dragged-container").style.top = (dragY - dragOffsetY - 10) + "px";
if (mostRecentHoveredDropTargetId!="") {
if (dragX<mostRecentHoveredDropTargetRect.left || dragX>mostRecentHoveredDropTargetRect.right || dragY<mostRecentHoveredDropTargetRect.top || dragY>mostRecentHoveredDropTargetRect.bottom) {
document.getElementById(mostRecentHoveredDropTargetId).classList.remove("drop-target-hover");
mostRecentHoveredDropTargetId = "";
}
}
});
document.body.addEventListener('drop', function (ev) {
console.log("drop event triggered");
ev.preventDefault();
var data = ev.dataTransfer.getData("text"); // data set to the id of the draggable element
if (document.getElementById(data)!=null) {
document.getElementById(data).classList.remove("dragged");
document.getElementById("dragged-container").innerHTML = "";
document.getElementById("dragged-container").style.display = "none";
var draggablesClasses = document.getElementById(data).className;
if ((draggablesClasses.indexOf('draggable')==-1 || draggablesClasses=="") && document.getElementById(data).getAttribute('draggable')=="true") {
if (draggablesClasses=="") {
document.getElementById(data).className += "draggable";
} else {
document.getElementById(data).className += " draggable";
}
}
}
});
// resets dragged-container and origin .draggable, when mouse released outside browser window
document.body.addEventListener('mouseleave', function (ev) {
if (jqueryReady==true) {
$(".dragged").addClass("draggable");
$(".dragged").removeClass("dragged");
}
document.getElementById("dragged-container").innerHTML = "";
document.getElementById("dragged-container").style.display = "none";
});
This is all working fine. The drag and drop performs exactly as I expect.
The problem is when I go to another page, obviously those body event listeners are still running.
I've seen a number of answers here and have tried everything I've seen. For starters this:
window.onunload = function() {
console.log("about to clear event listeners prior to leaving page");
document.body.removeEventListener('dragover', null);
document.body.removeEventListener('drop', null);
document.body.removeEventListener('mouseleave', null);
return;
}
...but the console.log output doesn't even appear (let alone the 'null's being wrong, I'm pretty sure). I've also tried this, in the jQuery ready function:
$(window).bind('beforeunload', function(){
console.log("about to clear event listeners prior to leaving page");
document.body.removeEventListener('dragover', null);
document.body.removeEventListener('drop', null);
document.body.removeEventListener('mouseleave', null);
});
..but, once again, the console isn't even receiving that output.
I have also tried both the above with 'onbeforeunload' AND 'onunload'.
What am I doing wrong? - specifically to do with removing these window.body event listeners, I mean (Anything else I can sort out later).
Thanks.

removeEventListener requires the handler
Don't use anonymous functions is the solution.
Like this:
var dragHandler = function (ev) {
console.log("dragover event triggered");
};
document.body.addEventListener('dragover', dragHandler);
and after:
window.onunload = function() {
console.log("about to clear event listeners prior to leaving page");
document.body.removeEventListener('dragover', dragHandler);
return;
}

Can I toggle popup after a click event with a mouseout event?

I'm using twitter bootstrap to display popovers with a click event. I'm requesting the info with the click event but I want to hide the popover after it looses focus so the user isn't required to click it again. Is this possible?
Basically I want to show the popover with a click event but then when the launch point looses focus from the mouse the popover is hidden.
Here is a link to the popover doc from twitter-bootstrap: http://twitter.github.com/bootstrap/javascript.html#popovers
This is what I'm currently doing:
jQuery:
$('.knownissue').on('click', function() {
var el = $(this);
if (el.data('showissue') == 'true') {
el.popover('toggle');
el.data('showissue', 'false');
return;
}
$.post('functions/get_known_issues.php', function(data) {
if (data.st) {
el.attr('data-content', data.issue);
el.popover('toggle');
el.data('showissue', 'true');
}
}, "json");
});
Any thoughts?

The following should work.
$('.knownissue').mouseleave(function() {
$(this).popover('hide');
});

Here is a custom jQuery event I call 'clickoutside'. It gets fired if and only if you click the mouse outside of the target element. It could easily be adapted for other event types (mousemove, keydown, etc). In your case, when fired it could close your modal.
(function ($) {
var count = 0;
$.fn.clickoutside = function (handler) {
// If the source element does not have an ID, give it one, so we can reference it
var self = $(this);
var id = self.attr('id');
if (id === '') {
id = 'clickoutside' + count++;
self.attr('id', id);
}
// Watch for the event everywhere
$('html').click(function (e) {
var source = $(e.target);
// ... but, stop it from propagating if it is inside the target
// element. The result being only events outside the target
// propagate to the top.
if (source.attr('id') == id || source.parents('#' + id).length > 0) {
return;
}
handler.call(this, e);
})
};
})(jQuery);
$('#targetElement').clickoutside(function(){
});
EDIT: Example JSFiddle.

How do I handle these events and why is my code not working?

I need to do the following. As soon as the user clicks on a div, i want to save the mouse coordinations while the user is moving the cursor over the div and is holding the left mouse button. When the user leaves the div or releases the left button, i want to stop recording the coordinates. I've got the following code:
$(document).ready(function() {
var coordhdl = new coordinateHandler();
$("#test").mousedown(function(e) {
$("#test").mousemove(function(ee) {
$("#test").mouseup(function(e) {
stopIt = true;
});
if(stopIt == false)
{
coordhdl.addCords(ee.pageX - this.offsetLeft, ee.pageY - this.offsetTop);
}
});
});
});
The problems with this code are:
It records coordinate even when the user only clicked the div without pressing the left button.
It doesn't stop recording the coordinates once it has been clicked.
I am new to Javascript/jQuery, so I don't know very much about it.

Something like this should work. It sets a flag to true/false when the mouse is pressed/released respectively. When the mouse moves, if the flag is set, the coordinates are added:
$(document).ready(function() {
var isDown = false,
coordhdl = new coordinateHandler();
$("#test").mousedown(function() {
isDown = true;
}).mouseup(function() {
isDown = false;
}).mousemove(function(e) {
if(isDown) {
coordhdl.addCords(ee.pageX - this.offsetLeft, ee.pageY - this.offsetTop);
}
});
});
Here's a demo of something similar in action (it simply writes the coordinates to a p element instead of using your coordinateHandler object).

Don't attach the event handlers inside the event handlers. On every mouse move you attach a new mouseup event handler. They don't get overridden, they get appended.
Use a "global" flag instead:
$(document).ready(function() {
var coordhdl = new coordinateHandler(),
recording = false;
$("#test").mousedown(function(e) {
recording = true;
}).mousemove(function(e) {
if(recording) {
coordhdl.addCords(e.pageX - this.offsetLeft, e.pageY - this.offsetTop);
}
}).mouseup(function(e) {
recording = false;
});
});

Every time there is a mousedown event, you add a mousemove handler, and every time the mouse moves, you add another mouseup handler. I can't see where the stopIt variable is declared so the scope of this variable may also be an issue. You don't need to nest the handlers, so try it this way.
$(document).ready(function() {
var coordhdl = new coordinateHandler();
var isRecording = false;
$("#test").mousedown(function(e) { isRecording = true })
.mouseup(function(e) { isRecording = false })
.mousemove(function(ee) {
if(isRecording)
{
coordhdl.addCords(ee.pageX - this.offsetLeft, ee.pageY - this.offsetTop);
}
});
});