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why does my custom-made "cursor" falls behind the moving div elements when i hover over them?

hello everyone hope you guys are having a great day!
so, i am building a simple game where I use a custom-made cursor as the aim for shooting div elements moving around the screen as the enemies and when i apply the "pointerdown" event i want the enemy to change its color. however, every time i hover over the enemy the cursor falls behind witch i don't understand why, and when i use the z-index property it will prevent the "pointerdown" event from firing. if some cool OG programmer can help me, it would mean a lot to me.
style
* {
margin: 0;
padding: 0;
cursor: none;
}
.aim {
position: absolute;
background: black;
width: 10px;
height: 10px;
border-radius: 50%;
transform: translate(-50%, -50%);
}
.enemy {
position: absolute;
border: 3px solid black;
background-color: blue;
width: 50px;
height: 50px;
}
javascript
const body = document.body;
const aim = document.createElement("div");
const enemy = document.createElement("div");
body.appendChild(aim);
body.appendChild(enemy);
aim.classList.add("aim");
enemy.classList.add("enemy");
let enemy_X_position = 0;
let enemy_Y_position = 0;
let enemy_X_distance = 1;
let enemy_Y_distance = 1;
function Flight()
{
enemy.style.left = enemy_X_position + "px";
enemy.style.top = enemy_Y_position + "px";
}
setInterval(function()
{
enemy_X_position += enemy_X_distance;
enemy_Y_position += enemy_Y_distance;
if ((enemy_X_position + enemy.offsetWidth) >= window.innerWidth || enemy_X_position <= 0)
enemy_X_distance = -enemy_X_distance;
if ((enemy_Y_position + enemy.offsetHeight) >= window.innerHeight || enemy_Y_position <= 0)
enemy_Y_distance = -enemy_Y_distance;
Flight();
},1000/60)
window.onmousemove = function()
{
aim.style.left = event.pageX + "px";
aim.style.top = event.pageY + "px";
}
enemy.onpointerdown = function()
{
event.target.style.background = "red";
}
enemy.onpointerup = function()
{
event.target.style.background = null;
}

Update
The event is not triggering because pointerdown was received by aim when it sits on top of enemy.
To solve this, add pointer-events: none on aim class to prevent it from being the target of a pointer event.
More about pointer-events
Hope this will help!
.aim {
position: absolute;
background: black;
width: 10px;
height: 10px;
border-radius: 50%;
transform: translate(-50%, -50%);
pointer-events: none;
}
Original
Perhaps an over simplified solution, but it seems that if you reverse the order of appendChild, the aim should be stacked over enemy without additional styling.
Example:
body.appendChild(enemy);
body.appendChild(aim);
Because both elements are child of body, Unless there is other styling that override this stacking, the later one should be on top.

Reset current section counter when user manually scrolls up or down

I'm implementing button which will on click vertically scroll down for one team member. So far I have managed that one click scrolls down for one team member, but the code breaks when user manually scrolls back to top.
Here is working JSFiddle
My code
<main class="team container">
<div v-for='(element, index) in members' :id="element.specialId" class="team__member" v-show="activeIndex === index || widthSmall">
<div class="team__member__bio">
<div class="team__member__name">{{element.name}}</div>
</div>
</div>
<a class="scroll-more scroll-team" v-show="widthSmall" #click="move($event)" style="cursor: pointer;">
<span></span>{{ $t('scroll') }}
</a>
</main>
export default {
name: "Team",
data() {
return {
members: [
{
name: "Bojan Dovrtel",
specialId: 'bojan-div'
},
{
name: "Klemen Razinger",
specialId: 'kelemen-div'
},
{
name: "Davor Pečnik",
specialId: 'davor-div'
},
{
name: "Maja Katalinič",
specialId: 'maja-div'
},
{
name: "Petra Vovk",
specialId: 'petra-div'
}
],
secs: document.getElementsByClassName('team__member'),
currentSection: 0,
}
},
methods: {
move(e) {
if (this.currentSection < this.secs.length) {
if (this.currentSection === 3) {
this.widthSmall = false;
}
window.scroll({
top: this.secs[++this.currentSection].offsetTop,
left: 0,
behavior: 'smooth'
});
} else if (this.currentSection > 0) {
window.scroll({
top: this.secs[--this.currentSection].offsetTop,
left: 0,
behavior: 'smooth'
});
}
}
}
};
How can I detect that users have scrolled up and change the value of current section? If you have any additional informations, please let me know and I will provide. Thank you

You could iterate through the elements, finding the closest one whose offsetTop (+ offsetHeight) matches (or be in range of) the current window.scrollY offset as it scrolls, and then decide whether to scroll to the next element or "readjust" the offset:
new Vue({
el: '#app',
data() {
return {
members: [
{
name: "Bojan",
specialId: 'bojan-div'
},
{
name: "Klemen",
specialId: 'kelemen-div'
},
{
name: "Davor",
specialId: 'davor-div'
},
{
name: "Maja",
specialId: 'maja-div'
},
{
name: "Petra",
specialId: 'petra-div'
}
],
secs: document.getElementsByClassName('height'),
currentSection: 0
}
},
mounted() {
this.move();
},
methods: {
move() {
let y = window.scrollY;
let totalSection = this.secs.length;
for (let index = 0; index < totalSection; index++) {
let sec = this.secs[index];
if (sec.offsetTop === y) {
// currentSection matches current window.scrollY, so we want to move to the next section/element
// Math.min() to ensure it won't go out of range, capping at the length of the total elements.
this.currentSection = Math.min(index + 1, totalSection - 1);
// Or reset the index once it has scrolled all the way down
// this.currentSection = (index + 1) % totalSection;
break;
}
else if (sec.offsetTop >= y && y <= (sec.offsetTop + sec.offsetHeight)) {
// window.scrollY is currently between the matched element's offsetTop and offsetHeight.
// This is user-initiated scrolling, so let's just "readjust" the offset rather than scrolling to the next element.
this.currentSection = index;
break;
}
}
window.scroll({
top: this.secs[this.currentSection].offsetTop,
left: 0,
behavior: 'smooth'
});
}
},
})
.height {
background-color: grey;
height: 300px;
border: solid 2px black;
}
.scroll-team {
position: fixed;
top: calc(100vh - 6rem);
left: 50%;
z-index: 2;
display: inline-block;
-webkit-transform: translate(0, -50%);
transform: translate(0, -50%);
color: #fff;
letter-spacing: 0.1em;
text-decoration: none;
transition: opacity 0.3s;
}
.scroll-team a:hover {
opacity: 0.5;
}
.scroll-more {
padding-top: 60px;
font-size: 1.35rem;
}
.scroll-more span {
position: absolute;
top: 0;
left: 50%;
width: 46px;
height: 46px;
margin-left: -23px;
border: 1px solid #fff;
border-radius: 100%;
box-sizing: border-box;
background: rgba(255, 255, 255, 0.2);
}
.scroll-more span::after {
position: absolute;
top: 50%;
left: 50%;
content: "";
width: 16px;
height: 16px;
margin: -12px 0 0 -8px;
border-left: 1px solid #fff;
border-bottom: 1px solid #fff;
-webkit-transform: rotate(-45deg);
transform: rotate(-45deg);
box-sizing: border-box;
}
.scroll-more span::before {
position: absolute;
top: 0;
left: 0;
z-index: -1;
content: "";
width: 44px;
height: 44px;
box-shadow: 0 0 0 0 rgba(255, 255, 255, 0.1);
border-radius: 100%;
opacity: 0;
-webkit-animation: sdb03 3s infinite;
animation: sdb03 3s infinite;
box-sizing: border-box;
}
<script src="https://unpkg.com/vue"></script>
<div id="app">
<div class="height" v-for="(element, index) in members" :key="index">
{{ element.name }}
</div>
<a class="scroll-more scroll-team" #click="move" style="cursor: pointer;">
<span></span>
</a>
</div>

To detect that a user has scrolled, you can listen for the scroll event on the container that is being scrolled. In this case, that would be the root element, so you can use window to add the event listener.
One way to do achieve that would be to add and remove the scroll listener in the created and destroyed lifecycle hooks, as mentioned in this answer.
Note that the scroll event will also be fired when you trigger a scroll with window.scroll({...}), not just user scrolling. So, you'll need to take care of that.
I'd recommend adding some kind of throttle to the scroll event listener and then responding to all scroll events, post throttle, by changing the currentSection value.
For example, your scroll event handler can be:
...,
onScroll(e) {
if(this.throttle) {
clearTimeout(this.throttle);
}
this.throttle = setTimeout(() => (this.currentSection = this.findCurrentSection(e)), 300);
},
...
Where throttle is just a data member used to hold the timeout value. The logic to find the value of currentSection will only be triggered 300ms after the last scroll event. You can also use requestAnimationFrame to do this, as mentioned here.
findCurrentSection is just a basic method that iterates over the secs array to find, well, the current section based on the current scroll value.
...,
findCurrentSection(e) {
const curTop = document.documentElement.scrollTop;
for(let i=0, len=this.secs.length; i < len; ++i) {
const secTop = this.secs[i].offsetTop;
if(curTop === secTop) {
return i;
} else if(curTop < secTop) {
return Math.max(i-1, 0);
}
}
},
...
Note that since in this particular case the scrolling container is the root element, I'm using document.documentElement.scrollTop, but based on the context, you can get the required value from the corresponding ScrollEvent (e in this case).
Here's a working fiddle based on your question. Also note that I have modified the move function according to the changes introduced.

Object with fixed Y-axis that follows the mouse on X-axis

I need help for an effect I'm trying to create: I made a CSS triangle and I want it to be fixed on the Y-axis but follow the mouse on his X-axis (didn't you read the title ?!). If it's not clear, I want it to move only to the left/right but not up/down. I managed to apply a js script I found on the internet to my triangle but I can't figure out how to change it to stop it from moving on the Y-axis. When I try to change anything, the whole thing doesn't move anymore. Can some one help me ?
// Here get the Div that you want to follow the mouse
var div_moving = document.getElementById('div_moving');
// Here add the ID of the parent element
var parent_div = 'parent_div';
// object to make a HTML element to follow mouse cursor ( http://coursesweb.net/ )
var movingDiv = {
mouseXY: {}, // will contain the X, Y mouse coords inside its parent
// Get X and Y position of the elm (from: vishalsays.wordpress.com/ )
getXYpos: function(elm) {
x = elm.offsetLeft; // set x to elm’s offsetLeft
y = elm.offsetTop; // set y to elm’s offsetTop
elm = elm.offsetParent; // set elm to its offsetParent
//use while loop to check if elm is null
// if not then add current elm’s offsetLeft to x, offsetTop to y and set elm to its offsetParent
while(elm != null) {
x = parseInt(x) + parseInt(elm.offsetLeft);
y = parseInt(y) + parseInt(elm.offsetTop);
elm = elm.offsetParent;
}
// returns an object with "xp" (Left), "=yp" (Top) position
return {'xp':x, 'yp':y};
},
// Returns object with X, Y coords inside its parent
getCoords: function(e) {
var xy_pos = this.getXYpos(e.target);
// if IE
if(navigator.appVersion.indexOf("MSIE") != -1) {
var standardBody = (document.compatMode == 'CSS1Compat') ? document.documentElement : document.body;
x = event.clientX + standardBody.scrollLeft;
y = event.clientY + standardBody.scrollTop;
}
else {
x = e.pageX;
y = e.pageY;
}
x = x - xy_pos['xp'];
y = y - xy_pos['yp'];
return {'xp':x, 'yp':y};
}
};
// registers 'mousemove' event to parent_div
document.getElementById(parent_div).addEventListener('mousemove', function(e){
mouseXY = movingDiv.getCoords(e);
div_moving.style.left = mouseXY.xp + 8 +'px';
div_moving.style.top = mouseXY.yp - 8 +'px';
});
#parent_div {
position: relative;
width: 100%;
height: 800px;
margin: 1em auto;
border; 1px solid #333;
background: #fefebe;
}
#div_moving {
position: absolute;
width: 41em;
height: 31em;
margin: 0;
border: 1px solid #33f;
background: #88ee99;
overflow:hidden;
}
.container {
width: 37.5em;
height: 37.5em;
position: relative;
border-top: 20px solid #e74c3c;
left:3%;
}
.triangle {
position: relative;
margin: auto;
top: -20em;
left: 0;
right: 0;
width:31em;
height:31em;
transform: rotate(45deg);
-webkit-transform: rotate(45deg);
-moz-transform: rotate(45deg);
-o-transform: rotate(45deg);
-ms-transform: rotate(45deg);
border-right: 20px solid #e74c3c;
border-bottom: 20px solid #e74c3c;
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div id="parent_div">
<div id="div_moving">
<div class="container">
<div class="triangle"></div>
</div>
</div>
Content in parent ...
</div>

I just reformatted a little, then commented one line and it's working in Chrome on my machine. Is this what you're looking for?
<html>
<head>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<script language="javascript">
// object to make a HTML element to follow mouse cursor ( http://coursesweb.net/ )
var movingDiv = {
mouseXY: {}, // will contain the X, Y mouse coords inside its parent
// Get X and Y position of the elm (from: vishalsays.wordpress.com/ )
getXYpos: function(elm) {
x = elm.offsetLeft; // set x to elm’s offsetLeft
y = elm.offsetTop; // set y to elm’s offsetTop
elm = elm.offsetParent; // set elm to its offsetParent
//use while loop to check if elm is null
// if not then add current elm’s offsetLeft to x, offsetTop to y and set elm to its offsetParent
while(elm != null) {
x = parseInt(x) + parseInt(elm.offsetLeft);
y = parseInt(y) + parseInt(elm.offsetTop);
elm = elm.offsetParent;
}
// returns an object with "xp" (Left), "=yp" (Top) position
return {'xp':x, 'yp':y};
},
// Returns object with X, Y coords inside its parent
getCoords: function(e) {
var xy_pos = this.getXYpos(e.target);
// if IE
if(navigator.appVersion.indexOf("MSIE") != -1) {
var standardBody = (document.compatMode == 'CSS1Compat') ? document.documentElement : document.body;
x = event.clientX + standardBody.scrollLeft;
y = event.clientY + standardBody.scrollTop;
}
else {
x = e.pageX;
y = e.pageY;
}
x = x - xy_pos['xp'];
y = y - xy_pos['yp'];
return {'xp':x, 'yp':y};
}
};
$(document).ready(function() {
// Here get the Div that you want to follow the mouse
var div_moving = document.getElementById('div_moving');
// Here add the ID of the parent element
var parent_div = 'parent_div';
// registers 'mousemove' event to parent_div
document.getElementById(parent_div).addEventListener('mousemove', function(e){
mouseXY = movingDiv.getCoords(e);
div_moving.style.left = mouseXY.xp + 8 +'px';
//div_moving.style.top = mouseXY.yp - 8 +'px';
});
});
</script>
<style>
#parent_div {
position: relative;
width: 100%;
height: 800px;
margin: 1em auto;
border; 1px solid #333;
background: #fefebe;
}
#div_moving {
position: absolute;
width: 41em;
height: 31em;
margin: 0;
border: 1px solid #33f;
background: #88ee99;
overflow:hidden;
}
.container {
width: 37.5em;
height: 37.5em;
position: relative;
border-top: 20px solid #e74c3c;
left:3%;
}
.triangle {
position: relative;
margin: auto;
top: -20em;
left: 0;
right: 0;
width:31em;
height:31em;
transform: rotate(45deg);
-webkit-transform: rotate(45deg);
-moz-transform: rotate(45deg);
-o-transform: rotate(45deg);
-ms-transform: rotate(45deg);
border-right: 20px solid #e74c3c;
border-bottom: 20px solid #e74c3c;
}
</style>
</head>
<body>
<div id="parent_div">
<div id="div_moving">
<div class="container">
<div class="triangle"></div>
</div>
</div>
Content in parent ...
</div>
</body>
</html>
Differences:
Load the JQuery script first
Process the listener in a ready function so all the content has been loaded
Comment out the Y positioning

EDIT: I found a solution to my problem.
So here the problems and what I did:
I wanted the object to move only on X-axis and not Y: IgnusFast found out the line to delete was "div_moving.style.top = mouseXY.yp - 8 +'px';"
I wanted it to stop staggering when the mouse passed over it: deleted "parseInt(x) +" in "while(elm != null) {x = parseInt(x) + parseInt(elm.offsetLeft); elm = elm.offsetParent;}" (makes the div stay where it is when not sure.
I wanted it to center with the mouse instead of being on its right: original was " div_moving.style.left = mouseXY.xp + 8 +'px';" wich made it go 8 pixels to the right of the current mouse's coordinates so I just used a negative number and place like this :" div_moving.style.left = mouseXY.xp + -350 +'px';"

How to control md-select drop down position in Angular Material

I need to customize a md-select so that the option list acts more like a traditional select. The options should show up below the select element instead of hovering over top of the element. Does anyone know of something like this that exists, or how to accomplish this?

This applies to Material for Angular 2+
Use disableOptionCentering option, such as:
<mat-select disableOptionCentering>
<mat-option *ngFor="let movie of movies" [value]="movie.value">
{{ movie.viewValue }}
</mat-option>
</mat-select>

Here you go - CodePen
Use the md-container-class attribute. From the docs:
Markup
<div ng-controller="AppCtrl" class="md-padding" ng-cloak="" ng-app="MyApp">
<md-input-container>
<label>Favorite Number</label>
<md-select ng-model="myModel" md-container-class="mySelect">
<md-option ng-value="myVal" ng-repeat="myVal in values">{{myVal.val}}</md-option>
</md-select>
</md-input-container>
</div>
CSS
.mySelect md-select-menu {
margin-top: 45px;
}
JS
(function () {
'use strict';
angular
.module('MyApp',['ngMaterial', 'ngMessages', 'material.svgAssetsCache'])
.controller('AppCtrl', function($scope) {
$scope.required = "required";
$scope.values = [
{val:1, des: 'One'},
{val:2, des: 'Two'}
];
});
})();

Hi maybe try something like this:
$('.dropdown-button2').dropdown({
inDuration: 300,
outDuration: 225,
constrain_width: false, // Does not change width of dropdown to that of the activator
hover: true, // Activate on hover
gutter: ($('.dropdown-content').width()*3)/2.5 + 5, // Spacing from edge
belowOrigin: false, // Displays dropdown below the button
alignment: 'left' // Displays dropdown with edge aligned to the left of button
}
);
https://jsfiddle.net/fb0c6b5b/
One post seems have the same issue: How can I make the submenu in the MaterializeCSS dropdown?

To people who has cdk-overlay (cdk-panel) with md-select.
Suppose that you use Angular 2, Typescript, Pug and Material Design Lite (MDL) in working environment.
Function which styles md-select works on click.
Javascript (TypeScript) in component
#Component({
selector: ..,
templateUrl: ..,
styleUrl: ..,
// For re-calculating on resize
host: { '(window:resize)': 'onResize()' }
})
export class MyComponent {
//Function to style md-select BEGIN
public styleSelectDropdown(event) {
var bodyRect = document.body.getBoundingClientRect();
let dropdown = document.getElementsByClassName("cdk-overlay-pane") as HTMLCollectionOf<HTMLElement>;
if (dropdown.length > 0) {
for(var i = 0; i < dropdown.length; i++) {
dropdown[i].style.top = "auto";
dropdown[i].style.bottom = "auto";
dropdown[i].style.left = "auto";
}
for(var i = 0; i < dropdown.length; i++) {
if (dropdown[i].innerHTML != "") {
var getDropdownId = dropdown[i].id;
document.getElementById(getDropdownId).classList.add('pane-styleSelectDropdown');
}
}
}
let target = event.currentTarget;
let selectLine = target.getElementsByClassName("mat-select-underline") as HTMLCollectionOf<HTMLElement>;
if (selectLine.length > 0) {
var selectLineRect = selectLine[0].getBoundingClientRect();
}
let targetPanel = target.getElementsByClassName("mat-select-content") as HTMLCollectionOf<HTMLElement>;
if (targetPanel.length > 0) {
var selectLineRect = selectLine[0].getBoundingClientRect();
}
if (dropdown.length > 0) {
for(var i = 0; i < dropdown.length; i++) {
dropdown[i].style.top = selectLineRect.top + "px";
dropdown[i].style.bottom = 0 + "px";
dropdown[i].style.left = selectLineRect.left + "px";
}
}
var windowHeight = window.outerHeight;
if (targetPanel.length > 0) {
targetPanel[0].style.maxHeight = window.outerHeight - selectLineRect.top + "px";
}
}
public onResize() {
this.styleSelectDropdown(event);
}
//Function to style md-select END
}
HTML (Pug)
.form-container
div.styleSelectDropdown((click)="styleSelectDropdown($event)")
md-select.form-group(md-container-class="my-container", id = '...',
md-option(....)
CSS which overrides Material Design Lite (MDL) css
.pane-styleSelectDropdown .mat-select-panel {
border: none;
min-width: initial !important;
box-shadow: none !important;
border-top: 2px #3f51b5 solid !important;
position: relative;
overflow: visible !important;
}
.pane-styleSelectDropdown .mat-select-panel::before {
content: "";
position: absolute;
top: -17px;
right: 0;
display: block;
width: 0;
height: 0;
border-left: 5px solid transparent;
border-right: 5px solid transparent;
border-top: 5px solid #3f51b5;
margin: 0 4px;
z-index: 1000;
}
.pane-styleSelectDropdown .mat-select-content {
border: 1px solid #e0e0e0;
box-shadow: 0 2px 1px #e0e0e0;
position: relative;
}
#media screen and (max-height: 568px) {
.pane-styleSelectDropdown .mat-select-content {
overflow-y: scroll;
}
}
.pane-styleSelectDropdown.cdk-overlay-pane {
top: 0;
bottom: 0;
left: 0;
overflow: hidden;
padding-bottom: 5px;
z-index: 10000;
}
.pane-styleSelectDropdown .mat-select-panel .mat-option.mat-selected:not(.mat-option-multiple),
.pane-styleSelectDropdown .mat-option:focus:not(.mat-option-disabled),
.pane-styleSelectDropdown .mat-option:hover:not(.mat-option-disabled) {
background: #fff !important;
}
.pane-styleSelectDropdown .mat-option {
line-height: 36px;
height: 36px;
font-size: 14px;
}

So this turned out to be something I had to do with Javascript and setTimeout, as ugly as the solution is. You can't effectively do this with CSS only as material design uses javascript positioning of the drop down. As a result I had to attach a function to the popup opening inside there I set a 200ms timeout that calculates the desired position of the drop down on the screen and moves it there. I also attached a function in the controller to a window resize event so it will move with a resize.
Ultimately you have to use a timeout to get material design time to do it's javascript based move of the popover and then move it yourself. I also uses a trick to hide it while the moving is taking place so the user doesn't see the jump. That's the description of what I had to do just in case someone else attempts similar.

You must override "top" of the CSS class ".md-select-menu-container".
To do so, you have to use the attribute md-container-class like:
md-container-class="dropDown"
inside the md-select tag. then you just have to create a custom css for the class declared:
.md-select-menu-container.dropDown{
top: 147px !important;
}
!important is the key here! top is the value you want... in this case 147px.
here's a CodePen

Modifying cursor property for select portion of an element

I have this HTML that renders a simple arrow sign pointing towards the right:
<!DOCTYPE html>
<html>
<head>
<style>
div { width: 0px; height: 0px; border-left: 20px solid black; border-top: 20px solid transparent; border-bottom: 20px solid transparent; border-right: 20px solid transparent; position: absolute; left: 35px; top: 53px; cursor: pointer; }
</style>
<body>
<div></div>
</body>
</html>
If you hover of it, the cursor turns to pointer. But because it is actually a square div, the cursor turns pointer even if you are just outside the arrow within the perimeter of the div.
So I wrote this Javascript addition such that the cursor turns pointer only when the mouse is hovering over that arrow. For this purpose, I figured the coordinates of the three vertices of the triangle from Firebug ((35,53),(55,73),(35,93) clockwise from top). Then I check whether the point in question lies inside the triangle formed by these 3 vertices. This I do by checking whether the point and the opposite vertex for each edge lies on the same side of that edge or not (if they do, the product of the values obtained by substituting the coordinates of that point for x and y in that equation will be positive).
<!DOCTYPE html>
<html>
<head>
<style>
div { width: 0px; height: 0px; border-left: 20px solid black; border-top: 20px solid transparent; border-bottom: 20px solid transparent; border-right: 20px solid transparent; position: absolute; left: 35px; top: 53px; }
.hoverclass { cursor: pointer; }
</style>
<script src="jquery.js">
</script>
<script>
$(document).ready(function(){
$("div").click(function(e) { alert(e.pageX + " " + e.pageY); });
function l1(x,y) { return y - x - 18; }
function l2(x,y) { return x+y-128; }
function l3(x,y) { return x-35; }
$("div").hover(function(e) {
var x = e.pageX;
var y = e.pageY;
if (l1(x,y)*l1(35,93) >= 0 && l1(x,y)*l1(35,93) >= 0 && l1(x,y)*l1(35,93) >= 0 ) {
$(this).addClass('hoverclass');
}
else { $(this).removeClass('hoverclass'); }
},
function() {
$(this).removeClass('hoverclass');
});
});
</script>
<body>
<div></div>
</body>
</html>
However, the results are not predictable. Sometimes the cursor turns pointer within the triangle only, sometimes outside as well (just as before), and sometimes not at all. I suspect that this is probably due to the hover function working overtime, that may be temporarily hanging the script. Is there any other way to achieve this?

This could be done using HTML5 canvas. Basic idea is to check for pixel color on mousemove on canvas element. This way, your element can be of any form as you wish. Of course, you should make some optimization of following code:
SEE WORKING DEMO
function findPos(obj) {
var curleft = 0, curtop = 0;
if (obj.offsetParent) {
do {
curleft += obj.offsetLeft;
curtop += obj.offsetTop;
} while (obj = obj.offsetParent);
return { x: curleft, y: curtop };
}
return undefined;
}
// set up triangle
var example = document.getElementById('example');
var context = example.getContext('2d');
context.fillStyle = '#000';
context.strokeStyle = '#f00';
context.lineWidth = 1;
context.beginPath();
// Start from the top-left point.
context.moveTo(10, 10); // give the (x,y) coordinates
context.lineTo(60, 60);
context.lineTo(10, 120);
context.lineTo(10, 10);
// Done! Now fill the shape, and draw the stroke.
// Note: your shape will not be visible until you call any of the two methods.
context.fill();
context.stroke();
context.closePath();
$('#example').mousemove(function(e) {
var pos = findPos(this);
var x = e.pageX - pos.x;
var y = e.pageY - pos.y;
var coord = "x=" + x + ", y=" + y;
var c = this.getContext('2d');
var p = c.getImageData(x, y, 1, 1).data;
if(p[3]!='0') $(this).css({cursor:'pointer'});
else $(this).css({cursor:'default'});
});

You'd better use CSS instead. With :before and :after pseudo classes you can do magic. Check out this Pure CSS GUI icons by Nicolas Gallagher.
If you use any CSS pre-processor, these icons can be wrapped up as a mixin, this way required properties can be assigned like this:
#icon > .close(16px, #fff, #E83921);

You can make any shape have cursor pointer with CSS only. The idea is to rotate wrapper container which has overflow: hidden (you can have several of them depending on the shape you need). In case of OP problem this code does a trick:
<div class="arrow"><i></i></div>
.arrow {
margin: 100px;
border_: 1px red solid;
width: 40px;
height: 40px;
overflow: hidden;
-webkit-transform: rotate(45deg);
transform: rotate(45deg);
}
.arrow i {
height: 65px;
width: 65px;
background-color: green;
content: '';
display: block;
cursor: pointer;
margin: -35px 0 0 11px;
-webkit-transform: rotate(45deg);
transform: rotate(45deg);
}
See this demo: http://cssdesk.com/PaB5n
True that this requires CSS transform support so it's not cross browser.