JavaScript - Stop laser once its in its incrementation cycle - javascript

To see a working example simply copy code into notepad++ and run in chrome as a .html file, I have had trouble getting a working example in snippet or code pen, I would have given a link to those websites if I could get it working in them.
The QUESTION is; once I fire the laser once it behaves exactly the way I want it to. It increments with lzxR++; until it hits boarder of the game arena BUT if I hit the space bar WHILST the laser is moving the code iterates again and tries to display the laser in two places at once which looks bad and very choppy, so how can I get it to work so the if I hit the space bar a second time even whilst the laser was mid incrementation - it STOPS the incrementing and simply shoots a fresh new laser without trying to increment multiple lasers at once???
below is the Code:
<html>
<head>
<style>
#blueCanvas {
position: absolute;
background-color: black;
width: 932px;
height: 512px;
border: 1px solid black;
top: 20px;
left: 20px;
}
#blueBall {
position: relative;
background-color: white;
border: 1px solid blue;
width: 10px;
height: 10px;
border-radius: 100%;
top: 0px;
left: 0px;
}
#laser {
position: absolute;
background-color: white;
border: 1px solid blue;
width: 10px;
height: 1px;
top: 10px;
left: 10px;
}
#pixelTrackerTop {
position: absolute;
top: 530px;
left: 20px;
}
#pixelTrackerLeft {
position: absolute;
top: 550px;
left: 20px;
}
</style>
<title>Portfolio</title>
<script src="https://ajax.googleapis.com/
ajax/libs/jquery/1.12.4/jquery.min.js">
</script>
<SCRIPT LANGUAGE="JavaScript" type="text/javascript">
document.addEventListener("keydown", keyBoardInput);
var topY = 0;
var leftX = 0;
var lzrY = 0;
var lzrX = 0;
function moveUp() {
var Y = document.getElementById("blueBall");
topY = topY -= 1;
Y.style.top = topY;
masterTrack();
if (topY < 1) {
topY = 0;
Y.style.top = topY;
};
stopUp = setTimeout("moveUp()", 1)
/**allows for progression of speed with additional key strokes**/
topStop();
stopConflictYup();
console.log('moveUp');
};
function moveDown() {
var Y = document.getElementById("blueBall");
topY = topY += 1;
Y.style.top = topY;
masterTrack();
if (topY > 500) {
topY = 500;
Y.style.top = topY;
};
stopDown = setTimeout("moveDown()", 1)
/**allows for progression of speed with additional key strokes**/
topStop();
stopConflictYdown();
console.log('moveDown');
};
function moveLeft() {
var X = document.getElementById("blueBall");
leftX = leftX -= 1;
X.style.left = leftX;
masterTrack();
if (leftX < 1) {
leftX = 0;
Y.style.leftX = leftX;
};
stopLeft = setTimeout("moveLeft()", 1)
/**allows for progression of speed with additional key strokes**/
leftStop();
stopConflictXleft();
console.log('moveLeft');
};
function moveRight() {
var X = document.getElementById("blueBall");
leftX = leftX += 1;
X.style.left = leftX;
masterTrack();
if (leftX > 920) {
leftX = 920;
Y.style.leftX = leftX;
};
stopRight = setTimeout("moveRight()", 1)
/**allows for progression of speed with additional key strokes**/
leftStop();
stopConflictXright();
console.log('moveRight');
};
function masterTrack() {
var pxY = topY;
var pxX = leftX;
document.getElementById('pixelTrackerTop').innerHTML =
'Top position is ' + pxY;
document.getElementById('pixelTrackerLeft').innerHTML =
'Left position is ' + pxX;
};
function topStop() {
if (topY <= 0) {
clearTimeout(stopUp);
console.log('stopUp activated');
};
if (topY >= 500) {
clearTimeout(stopDown);
console.log('stopDown activated');
};
};
function leftStop() {
if (leftX <= 0) {
clearTimeout(stopLeft);
console.log('stopLeft activated');
};
if (leftX >= 920) {
clearTimeout(stopRight);
console.log('stopRight activated');
};
};
function stopConflictYup() {
clearTimeout(stopDown);
};
function stopConflictYdown() {
clearTimeout(stopUp);
};
function stopConflictXleft() {
clearTimeout(stopRight);
};
function stopConflictXright() {
clearTimeout(stopLeft);
};
function shootLaser() {
var l = document.getElementById("laser");
var lzrY = topY;
var lzrX = leftX;
fireLaser();
function fireLaser() {
l.style.left = lzrX; /**initial x pos **/
l.style.top = topY; /**initial y pos **/
var move = setInterval(moveLaser, 1);
/**continue to increment laser unless IF is met**/
function moveLaser() { /**CALL and start the interval**/
var bcrb = document.getElementById("blueCanvas").style.left;
if (lzrX > bcrb + 920) {
/**if the X axis of the laser goes beyond the
blueCanvas 0 point by 920 then stop incrementing the laser on its X
axis**/
clearInterval(move);
/**if statement was found true so stop increment of laser**/
} else {
lzrX++;
l.style.left = lzrX;
};
};
};
};
function keyBoardInput() {
var i = event.keyCode;
if (i == 32) {
shootLaser();
};
if (i == 38) {
if (topY > 0) {
moveUp();
};
};
if (i == 40) {
if (topY < 500) {
moveDown();
};
};
if (i == 37) {
if (leftX > 0) {
moveLeft();
};
};
if (i == 39) {
if (leftX < 920) {
moveRight();
};
};
};
/**
!! gradual progression of opacity is overall
!! being able to speed up element is best done with setTimout
!! setInterval is constant regards to visual speed
!! NEXT STEP IS ARRAYS OR CLASSES
IN ORDER TO SHOOT MULITPLE OF SAME ELEMENT? MAYBEE?
var l = document.getElementById("laser");
lzrX = lzrX += 1;
l.style.left = lzrX;
lzrY = topY += 1;
l.style.top = lzrY;
**/
</SCRIPT>
</head>
<div id="blueCanvas">
<div id="laser"></div>
<div id="blueBall">
</div>
</div>
<p id="pixelTrackerTop">Top position is 0</p>
<br>
<p id="pixelTrackerLeft">Left position is 0</p>
</body>
</html>

Solved the problem with using a variable called "g" and incrementing it once the laser is shot!
var g = 0;
function keyBoardInput() {
var i = event.keyCode;
if (i == 32) {
if (g < 1) {
shootLaser();
g++;
};
};

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You have more than one rain
This works better but you really ned a random step for each drop
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How to drag images in JS

I have a large background image and some much smaller images for the user to drag around on the background. I need this to be efficient in terms of performance, so i'm trying to avoid libraries. I'm fine with drag 'n' drop if it work's well, but im trying to get drag.
Im pretty much trying to do this. But after 8 years there must be a cleaner way to do this right?
I currently have a drag 'n' drop system that almost works, but when i drop the smaller images, they are just a little off and it's very annoying. Is there a way to fix my code, or do i need to take a whole different approach?
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event.preventDefault();
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let imgs = [
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"https://upload.wikimedia.org/wikipedia/commons/b/b4/Litoria_infrafrenata_-_Julatten.jpg"
]
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<!-- my html: -->
<style>
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height: 500px;
align-content: center;
margin: 150px auto 150px auto;
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.map .base {
position: absolute;
width: inherit;
height: inherit;
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height: 50px;
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</style>
<div class="map" onDrop="drop(event)" ondragover="allowDrop(event)">
<img src='https://upload.wikimedia.org/wikipedia/commons/f/f7/Plan-Oum-el-Awamid.jpg' alt="pohja" class="base" draggable="false">
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With the answers from here and some time i was able to get a smooth drag and click with pure js.
Here is a JSFiddle to see it in action.
let maxLeft;
let maxTop;
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const minTop = 0;
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"https://upload.wikimedia.org/wikipedia/commons/6/67/Orange_juice_1_edit1.jpg",
"https://upload.wikimedia.org/wikipedia/commons/f/ff/Solid_blue.svg",
"https://upload.wikimedia.org/wikipedia/commons/b/b4/Litoria_infrafrenata_-_Julatten.jpg"
]
var originalX;
var originalY;
window.onload = function() {
document.onmousedown = startDrag;
document.onmouseup = stopDrag;
}
function sensorClick () {
if (Date.now() - timeDelta < 150) { // check that we didn't drag
createPopup(this);
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}
// create a popup when we click
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let p = document.getElementById("popup");
if (p) {
p.parentNode.removeChild(p);
}
let popup = document.createElement("div");
popup.id = "popup";
popup.className = "popup";
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popup.style.left = parent.x - 75 + "px";
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popup.appendChild(text);
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map.appendChild(popup);
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var map = document.getElementsByClassName("map")[0];
let base = document.getElementsByClassName("base")[0];
maxLeft = base.width - 50;
maxTop = base.height - 50;
/* my smaller images: */
for (let i = 0; i < 6; i++) {
let sensor = document.createElement("img");
sensor.src = imgs[i % imgs.length];
sensor.alt = i;
sensor.id = i;
sensor.draggable = true;
sensor.classList.add("sensor");
sensor.classList.add("dragme");
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sensor.style.top = `${Math.floor(Math.random() * 500)}px`
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timeDelta = Date.now(); // get current millis
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position: absolute;
width: inherit;
height: inherit;
}
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width: 50px;
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left: 0px;
top: 0px;
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How to add a game menu

I am trying to add a generic game menu with "start" to initiate the game. How do I go about doing this? Here is the code:
var LEFT_KEY = 37;
var UP_KEY = 38;
var RIGHT_KEY = 39;
var DOWN_KEY = 40;
var SPACE_KEY = 32;
var HERO_MOVEMENT = 3;
var lastLoopRun = 0;
var score = 0;
var iterations = 0;
var controller = new Object();
var enemies = new Array();
function createSprite(element, x, y, w, h) {
var result = new Object();
result.element = element;
result.x = x;
result.y = y;
result.w = w;
result.h = h;
return result;
}
function toggleKey(keyCode, isPressed) {
if (keyCode == LEFT_KEY) {
controller.left = isPressed;
}
if (keyCode == RIGHT_KEY) {
controller.right = isPressed;
}
if (keyCode == UP_KEY) {
controller.up = isPressed;
}
if (keyCode == DOWN_KEY) {
controller.down = isPressed;
}
if (keyCode == SPACE_KEY) {
controller.space = isPressed;
}
}
function intersects(a, b) {
return a.x < b.x + b.w && a.x + a.w > b.x && a.y < b.y + b.h && a.y + a.h > b.y;
}
function ensureBounds(sprite, ignoreY) {
if (sprite.x < 20) {
sprite.x = 20;
}
if (!ignoreY && sprite.y < 20) {
sprite.y = 20;
}
if (sprite.x + sprite.w > 480) {
sprite.x = 480 - sprite.w;
}
if (!ignoreY && sprite.y + sprite.h > 480) {
sprite.y = 480 - sprite.h;
}
}
function setPosition(sprite) {
var e = document.getElementById(sprite.element);
e.style.left = sprite.x + 'px';
e.style.top = sprite.y + 'px';
}
function handleControls() {
if (controller.up) {
hero.y -= HERO_MOVEMENT;
}
if (controller.down) {
hero.y += HERO_MOVEMENT;
}
if (controller.left) {
hero.x -= HERO_MOVEMENT;
}
if (controller.right) {
hero.x += HERO_MOVEMENT;
}
if (controller.space) {
var laser = getFireableLaser();
if (laser) {
laser.x = hero.x + 9;
laser.y = hero.y - laser.h;
}
}
ensureBounds(hero);
}
function getFireableLaser() {
var result = null;
for (var i = 0; i < lasers.length; i++) {
if (lasers[i].y <= -120) {
result = lasers[i];
}
}
return result;
}
function getIntersectingLaser(enemy) {
var result = null;
for (var i = 0; i < lasers.length; i++) {
if (intersects(lasers[i], enemy)) {
result = lasers[i];
break;
}
}
return result;
}
function checkCollisions() {
for (var i = 0; i < enemies.length; i++) {
var laser = getIntersectingLaser(enemies[i]);
if (laser) {
var element = document.getElementById(enemies[i].element);
element.style.visibility = 'hidden';
element.parentNode.removeChild(element);
enemies.splice(i, 1);
i--;
laser.y = -laser.h;
score += 100;
} else if (intersects(hero, enemies[i])) {
gameOver();
} else if (enemies[i].y + enemies[i].h >= 500) {
var element = document.getElementById(enemies[i].element);
element.style.visibility = 'hidden';
element.parentNode.removeChild(element);
enemies.splice(i, 1);
i--;
}
}
}
function gameOver() {
var element = document.getElementById(hero.element);
element.style.visibility = 'hidden';
element = document.getElementById('gameover');
element.style.visibility = 'visible';
}
function showSprites() {
setPosition(hero);
for (var i = 0; i < lasers.length; i++) {
setPosition(lasers[i]);
}
for (var i = 0; i < enemies.length; i++) {
setPosition(enemies[i]);
}
var scoreElement = document.getElementById('score');
scoreElement.innerHTML = 'SCORE: ' + score;
}
function updatePositions() {
for (var i = 0; i < enemies.length; i++) {
enemies[i].y += 4;
enemies[i].x += getRandom(7) - 3;
ensureBounds(enemies[i], true);
}
for (var i = 0; i < lasers.length; i++) {
lasers[i].y -= 12;
}
}
function addEnemy() {
var interval = 50;
if (iterations > 1500) {
interval = 5;
} else if (iterations > 1000) {
interval = 20;
} else if (iterations > 500) {
interval = 35;
}
if (getRandom(interval) == 0) {
var elementName = 'enemy' + getRandom(10000000);
var enemy = createSprite(elementName, getRandom(450), -40, 35, 35);
var element = document.createElement('div');
element.id = enemy.element;
element.className = 'enemy';
document.children[0].appendChild(element);
enemies[enemies.length] = enemy;
}
}
function getRandom(maxSize) {
return parseInt(Math.random() * maxSize);
}
function loop() {
if (new Date().getTime() - lastLoopRun > 40) {
updatePositions();
handleControls();
checkCollisions();
addEnemy();
showSprites();
lastLoopRun = new Date().getTime();
iterations++;
}
setTimeout('loop();', 2);
}
document.onkeydown = function(evt) {
toggleKey(evt.keyCode, true);
};
document.onkeyup = function(evt) {
toggleKey(evt.keyCode, false);
};
var hero = createSprite('hero', 250, 460, 20, 20);
var lasers = new Array();
for (var i = 0; i < 3; i++) {
lasers[i] = createSprite('laser' + i, 0, -120, 2, 50);
}
loop();
#hero {
/* background: #ff0000; */
background-image: url("man-of-space.png");
width: 40px;
height: 40px;
position: absolute;
}
#background {
background-image: url("space.png");
/* background: #000000; */
width: 500px;
height: 500px;
position: absolute;
left: 0px;
top: 0px;
}
.laser {
background: #00ff00;
width: 2px;
height: 50px;
position: absolute;
}
.enemy {
background-image: url("spaceship.png");
background-size: 40px 40px;
width: 40px;
height: 40px;
position: absolute;
}
#score {
color: #ffffff;
font-size: 18pt;
position: absolute;
left: 20px;
top: 20px;
}
#gameover {
color: #ff0000;
font-size: 20px;
position: absolute;
left: 160px;
top: 200px;
visibility: hidden;
}
<div id="background"></div>
<div id="hero"></div>
<div class="laser" id="laser0"></div>
<div class="laser" id="laser1"></div>
<div class="laser" id="laser2"></div>
<div id="score"></div>
<div id="gameover">GAME OVER</div>
You could wrap your game UI in a <div id="game" style="display: none;"> element so it will be hidden when the page is loaded. Then wrap your start menu in a <div id="startMenu"> element with a <button id="startButton">Start</button> that will be used to hide the start menu and show the game UI.
In your JS code you could wrap your game in a function so it can be started when you call it.
HTML:
<div id="startMenu">
<button id="startButton">Start</button>
</div>
<div id="game" style="display: none;">
<div id="background"></div>
<div id="hero"></div>
<div class="laser" id="laser0"></div>
<div class="laser" id="laser1"></div>
<div class="laser" id="laser2"></div>
<div id="score"></div>
<div id="gameover">GAME OVER</div>
</div>
JS:
function startGame() {
var LEFT_KEY = 37;
var UP_KEY = 38;
var RIGHT_KEY = 39;
var DOWN_KEY = 40;
var SPACE_KEY = 32;
var HERO_MOVEMENT = 3;
[...Your game code...]
loop();
}
document.getElementById('startButton').onclick = function() {
document.getElementById('startMenu').style.display = "none";
document.getElementById('game').style.display = "";
startGame();
};
Now you have a start menu (<div id="startMenu">) that you can customize however you like, and a game UI (<div id="game">) that will be shown only after the start button is pressed.
Add more HTML would be my suggestion. Maybe make a div that has all the start screen elements you need in it. When the start function happens, set that div's innerHTML to "".
Example:
document.getElementById('yourDivIdHere').innerHTML = '';

checkCollision function is not working in Array.forEach (check elements collision)

why my checkCollision function is not working in foreach loop ? I want to check whether obs (obstacle) is hits/overlaps on collector (gray object). I am checking every 1 millisecond using setInterval checkCollision function. Basically I am trying to build a simple car game. please help me and thank you in advance
let body = document.body[0];
let container = document.querySelector(".container");
let allObstacles = [];
let colors = ["green", "green", "red"];
let collector = document.getElementById("collector");
class Obstacle {
constructor(yPos) {
this.yPos = -50;
}
randomnum() {
let randX = Math.floor(Math.random() * (container.clientWidth - 50));
return randX;
}
createObstacle() {
let obstacle = document.createElement("div");
obstacle.classList.add("obstacle");
let bgColor = colors[Math.floor(Math.random() * colors.length)];
obstacle.style.width = "50px";
obstacle.style.height = "50px";
obstacle.style.position = "absolute";
obstacle.style.left = this.randomnum() + "px";
obstacle.style.top = this.yPos + "px";
obstacle.style.backgroundColor = bgColor;
obstacle.dataset.behave = bgColor;
container.appendChild(obstacle);
return obstacle;
}
element = this.createObstacle();
updatePosition() {
this.yPos += 2;
this.element.style.top = this.yPos + "px";
}
kill() {
this.element.remove();
}
}
let dropObs = setInterval(function() {
allObstacles.forEach(function(obs) {
obs.updatePosition();
});
allObstacles.forEach(function(obs) {
// why checkCollision function is not working?
if (checkCollision(obs, collector)) {
console.log("hit");
}
if (obs.yPos > container.clientHeight) {
obs.kill();
}
});
}, 10);
let generateObs = setInterval(function() {
let obs = new Obstacle();
allObstacles.push(obs);
}, 2000);
function checkCollision(obj1, obj2) {
var obj1Y = obj1.offsetTop;
var obj2Y = obj2.offsetTop;
var obj1X = obj1.offsetLeft;
var obj2X = obj2.offsetLeft;
if (
obj2Y + 100 >= obj1Y &&
obj2Y <= obj1Y + 100 &&
obj2X + 100 >= obj1X &&
obj2X <= obj1X + 100
) {
return 1;
}
}
* {
margin: 0;
padding: 0;
box-sizing: border-box;
outline: 0;
}
html,
body {
width: 100%;
height: 100%;
}
.container {
position: relative;
width: 100%;
height: 100%;
}
#collector {
width: 50px;
height: 100px;
background: gray;
position: absolute;
top: calc(100vh - 100px);
left: 50%;
margin-left: -25px;
}
<div class="container">
<div id="collector"></div>
</div>
The first thing you should not use setInterval for this type of animation. Use requestAnimationFrame
https://developer.mozilla.org/en-US/docs/Web/API/window/requestAnimationFrame
obj1X,obj1Y comming undefined.

Less javascript code for this loop animation?

I've done this simple animation but i have a feeling i've writted to much lines of code for such a simple task. Is there a way to achieve the same result but with less code ?
https://jsfiddle.net/qw82Lwy0/1/
function myMove() {
var elem = document.getElementById("animate");
var pos = 0;
var id = setInterval(frame, 5);
var flag = true;
function frame() {
if (flag) {
pos++;
elem.style.top = pos + 'px';
elem.style.left = pos + 'px';
if (pos == 350) {
flag = false;
}
} else if (!flag) {
pos--;
elem.style.top = pos + 'px';
elem.style.left = pos + 'px';
if (pos == 0) {
flag = true;
}
}
}
}
P.S: No jquery or css animation, just javascript.
instead of using the flag and a seperate code for the 2 conditions you could just flip the incrementer like so:
function myMove() {
var elem = document.getElementById("animate");
var pos = 0;
var id = setInterval(frame, 5);
var changeVal = 1;
function frame() {
pos+=changeVal;
if ((pos >= 350) || (pos <= 0)) changeVal *= -1;
elem.style.top = elem.style.left = pos + 'px';
}
}
Animations can now be done in modern browsers using CSS. For example, your javascript animation can be condensed to just a few lines using a CSS transition.
See MDN for more details and examples of transitions and animations.
Run the code snippet below to try
window.ball.addEventListener('transitionend', toggle);
function toggle() {
window.ball.classList.toggle('move');
}
.animation {
position: relative;
background-color: lightyellow;
border: 1px solid gray;
height: 200px;
width: 200px;
}
#ball {
transition-property: left top background-color;
transition-duration: 2s;
position: absolute;
background-color: red;
border-radius: 12px;
height: 25px;
width: 25px;
left: 0;
top: 0;
}
#ball.move {
background-color: blue;
left: 175px;
top: 175px;
}
<button onclick="toggle()">Start</button>
<div class="animation"><div id="ball"></div></div>
Well, you could shorten your frame() function like so:
function myMove() {
var elem = document.getElementById("animate");
var pos = 0;
var id = setInterval(frame, 5);
var flag = true;
function frame() {
if (flag) {
pos++;
if (pos == 350) {
flag = false;
}
} else { // since you are checking if flag is true, the only other answer is false
pos--;
if (pos == 0) {
flag = true;
}
}
elem.style.top = pos + 'px'; // since this occurs in both cases
elem.style.left = pos + 'px'; // you can do it afterward
}
}
Use a function with 3 paraneters : posAdd, flagValue and posValue
function frame(posAdd,flagValue,posValue) {
if (flagValue) {
pos=pos+posAdd;
elem.style.top = pos + 'px';
elem.style.left = pos + 'px';
if (pos == posValue) {
flag = !flagValue;
}
}
}
And call it twice : frame(1,true,350)
And frame(-1,false,0)

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