var arrow = document.getElementById("arrow");
function shot() {
var arrows = document.createElement("div");
document.body.appendChild(arrows);
arrows.style.backgroundColor = "black";
arrows.style.height = "80" + "px";
arrows.style.width = "3" + "px";
var arrowX = parseInt(document.arrow.style.left);
var arrowY = parseInt(document.arrow.style.top);
document.arrows.style.left = arrowX + "px";
document.arrows.style.top = arrowY + "px";
};
When I run it and click button which runs function shot it says it cannot read property "style" of undefined. It also spawns a new element on position it would spawn without any position defining.
Yep, my ids are correct.
Html:
<!DOCTYPE html>
<html>
<head>
<title>Page Title</title>
</head>
<body>
<div id="arrow"><div>
<button id="button" onclick="shot();"> Shot! </button>
</body>
</html>
CSS:
#arrow {
background-color: black;
height: 80px;
width: 1.5px;
position: relative;
left: 0px;
top: 0px;
}
Here is full project JS, which u dont need. Its not complete. There is button faster but it doesnt work, idk why. It should be archery game
var arrow = document.getElementById("arrow");
var arrowPos = -50;
var speed = 1000;
var speed2 = speed/100;
function arrow_move_right() {
arrowPos += 1;
arrow.style.left = arrowPos + "px";
if (arrowPos >= 280) {
return arrow_move_left()
}
else {
setTimeout(arrow_move_right, speed2);
};
};
function arrow_move_left() {
arrow = document.getElementById("arrow");
arrowPos -= 1;
arrow.style.left = arrowPos + "px";
if (arrowPos <= -50) {
return arrow_move_right()
}
setTimeout(arrow_move_left, speed2);
};
function faster() {
speed -= 100;
alert(speed)
}
function shot() {
var arrows = document.createElement("div");
document.body.appendChild(arrows);
arrows.style.backgroundColor = "black";
arrows.style.height = "80" + "px";
arrows.style.width = "1.5" + "px";
var arrowX = parseInt(arrow.style.left);
var arrowY = parseInt(arrow.style.top);
alert(arrowX);
alert(arrowY);
// arrows.style.left = arrowX;
// arrows.style.top = arrowY;
arrows.style.pos = "relative";
arrows.style.top = -50 + "px";
};
Hope this is what you are looking for!
var arrow = document.getElementById("arrow");
function shot() {
var arrows = document.createElement("div");
document.body.appendChild(arrows);
arrows.style.backgroundColor = "blue";
arrows.style.height = "80px";
arrows.style.width = "3px";
arrows.style.position = "absolute";
arrows.style.top = arrow.offsetTop + "px";
arrows.style.left = arrow.offsetLeft + "px";
};
#arrow {
height: 80px;
width: 3px;
background: black;
position: relative;
-webkit-animation: move 5s infinite; /* Safari 4.0 - 8.0 */
animation: move 5s infinite;
}
/* Styles for animating arrow */
/* Safari 4.0 - 8.0 */
#-webkit-keyframes move {
from {left: 0px;}
to {left: 400px;}
}
#keyframes move {
from {left: 0px;}
to {left: 400px;}
}
<div id="arrow"></div>
<button id="button" onclick="shot();"> Shot! </button>
Here is what I mean....
var arrow = document.getElementById("arrow");
function shot() {
var arrows = document.createElement("div");
document.body.appendChild(arrows);
arrows.style.backgroundColor = "black";
arrows.style.height = "80" + "px";
arrows.style.width = "3" + "px";
var arrowX = parseInt(arrow.style.left);
var arrowY = parseInt(arrow.style.top);
arrows.style.left = arrowX + "px";
arrows.style.top = arrowY + "px";
};
<!DOCTYPE html>
<html>
<head>
<title>Page Title</title>
</head>
<body>
<div id="arrow"><div>
<button id="button" onclick="shot();"> Shot! </button>
</body>
</html>
Related
I was trying to make some controls to the box move to left, right, up and down. But when i make all the functions in the script tag, it get an error (in all the four onclick button):
Function not defined at HTMLButtonElement.onclick
in the lines that i make the button tag.
<html>
<button onclick = "leftmove()" id = "b1"> Left </button>
<button onclick = "rightmove()" id = "b2"> Right </button>
<button onclick = "upmove()" id = "b3"> Up </button>
<button onclick = "downmove()" id = "b4"> Down </button>
<h1 id = "box"></h1>
<style type = "text/css">
#box {
width: 50px;
height: 50px;
background-color: black;
}
<script>
var box = document.getElementById("box");
function leftmove() {
margin += 2;
box.style.marginLeft = margin + "px";
}
var box = document.getElementById("box");
function rightmove() {
margin -= 2;
box.style.marginLeft = margin + "px";
}
var box = document.getElementById("box");
function upmove() {
margin += 2;
box.style.marginTop = margin + "px";
}
var box = document.getElementById("box");
function downmove() {
margin -= 2;
box.style.marginLeft = margin + "px";
}
</script>
</html>
When using <script> tags like this, the functions and targeted tags have to be defined before usage. To make you example work you have to split you script tag to first define you functions and set the box variable later, after you have defined the corresponding tag. Also the margin variable is missing, I added is as zero but that's probably not how you want it. Working example:
<html>
<body>
<script>
var margin = 0;
function leftmove() {
margin += 2;
box.style.marginLeft = margin + "px";
}
function rightmove() {
margin -= 2;
box.style.marginLeft = margin + "px";
}
function upmove() {
margin += 2;
box.style.marginTop = margin + "px";
}
var box = document.getElementById("box");
function downmove() {
margin -= 2;
box.style.marginLeft = margin + "px";
}
</script>
<button onclick="leftmove()" id="b1"> Left </button>
<button onclick="rightmove()" id="b2"> Right </button>
<button onclick="upmove()" id="b3"> Up </button>
<button onclick="downmove()" id="b4"> Down </button>
<h1 id="box"></h1>
<style type="text/css">
#box {
width: 50px;
height: 50px;
background-color: black;
}
</style>
<script>
var box = document.getElementById("box");
</script>
</body>
</html>
A few notes aside the question:
A <div> might be more appropriate instead of the <h1> for the box
For rendering performance you would be better of using transform(x, y) instead of margins to move the box
Some JavaScript variables were created to manipulate the CSS indirectly. Other elements were also implemented to better understand the movements.
<html>
<style type = "text/css">
#box {
margin: 100px;
width: 50px;
height: 50px;
background-color: black;
}
</style>
<button onclick = "start()" id = "b0"> Start </button>
<button onclick = "leftmove()" id = "b1"> Left </button>
<button onclick = "rightmove()" id = "b2"> Right </button>
<button onclick = "upmove()" id = "b3"> Up </button>
<button onclick = "downmove()" id = "b4"> Down </button>
<div id="box"></div>
<script type="text/javascript">
var box = document.getElementById("box");
var margin = 10;
var marginX = 100;
var marginY = 100;
function start(){
box.style.margin = "100px";
marginX = 100;
marginY = 100;
}
function leftmove() {
marginX -= margin;
box.style.marginLeft = marginX + "px";
}
function rightmove() {
marginX += margin;
box.style.marginLeft = marginX + "px";
}
function upmove() {
marginY -= margin;
box.style.marginTop = marginY + "px";
}
function downmove() {
marginY += margin;
box.style.marginTop = marginY + "px";
}
</script>
</html>
I have practiced one question and this is about checking time to click the shape that comes up. I want to save the the high score and compare with the next one coming up. It is just how to store the high score . It would be great help if somebody give the way to do it. Thank you in advance
<!doctype html>
<html>
<head>
<title> Javasript </title>
<style type="text/css">
#shape {
width: 200px;
height: 200px;
display:none;
position : relative;
}
</style>
</head>
<body>
<h1>Test your reaction </h1>
<p>Click on the boxes as soon as possible and win it </p>
<p>Your time taken <span id="timeTaken"></span></p>
<div id="shape"></div>
<script type="text/javascript">
var start = new Date().getTime();
function getRandomColor() {
var letters = '0123456789ABCDEF'.split('');
var color = '#';
for (var i = 0; i < 6; i++) {
color += letters[Math.floor(Math.random() * 16)];
}
return color;
}
function makeShapeAppear() {
var top = Math.random() * 400 ;
var left = Math.random() * 400 ;
var width = (Math.random() * 200) + 100 ;
if (Math.random()> 0.5) {
document.getElementById("shape").style.borderRadius = "50%";
} else {
document.getElementById("shape").style.borderRadius = "0%"; }
document.getElementById("shape").style.backgroundColor = getRandomColor();
document.getElementById("shape").style.height = top + 'px';
document.getElementById("shape").style.width = width + 'px';
document.getElementById("shape").style.top = top + 'px';
document.getElementById("shape").style.left = left + 'px';
document.getElementById("shape").style.height = top + 'px';
document.getElementById("shape").style.display = 'block';
start = new Date().getTime();
}
function appearAfterDelay() {
setTimeout(makeShapeAppear, Math.random() * 2000 );
}
appearAfterDelay();
document.getElementById("shape").onclick = function() {
document.getElementById("shape").style.display = 'none';
var end = new Date().getTime();
var timeTaken = (end - start)/1000;
document.getElementById("timeTaken").innerHTML = timeTaken + "s";
appearAfterDelay();
}
</script>
</body>
</html>
I'm a beginner in javascript and I'm trying to make a very simple game. I know that my code is not the best, but i want to make it working. I want to stop function nahoru() or make it move to the other way and after it touches the bottom of the page/100%, make it repeat.
<html>
<head>
<script>
function naloud() {
var elem = document.getElementById("krtek");
elem.style.top = '100%';
var eleme = document.getElementById("krtek2");
eleme.style.top = '100%';
var elemen = document.getElementById("krtek3");
elemen.style.top = '100%';
}
var pos = 100;
var los = 0;
function nahoru() {
var elemend = document.getElementById("batn");
elemend.style.opacity = '0';
var elem = document.getElementById("krtek");
var id = setInterval(frame, 30);
function frame() {
if (pos == 0) {
clearInterval(id);
document.write('<center>GAME OVER<br>YOUR SCORE: ' + skore +
'<br>Press F5 for restart.')
} else {
pos = pos - 1;
elem.style.top = pos + '%';
}
}
}
var skore = 0;
function pric() {
skore++;
document.getElementById("skore").innerHTML = "Skore: " + skore;
elem.style.top = '+100%';
}
</script>
<style>
.prvni {
position: absolute;
width: 10%;
height: 110%;
left: 10%;
background-color: brown;
}
.druhy {
position: absolute;
width: 10%;
height: 110%;
left: 45%;
background-color: brown;
}
.treti {
position: absolute;
width: 10%;
height: 110%;
left: 80%;
background-color: brown;
}
</style>
</head>
<body onload="naloud()">
<button onclick="nahoru()" id="batn">START</button>
<div id="skore">Skore: 0</div>
<div id="krtek" class="prvni" onclick="pric()"></div>
<div id="krtek2" class="druhy" onclick="pric()"></div>
<div id="krtek3" class="treti" onclick="pric()"></div>
</body>
</html>
Declare id outside nahoru function,
like here
var pos = 100;
var los = 0;
var id = null;
Set interval in nahoru function,
like this (important, remove var from here)
id = setInterval(frame, 30);
Now clear interval in pric function
like this
function pric(elem) {
skore++;
clearInterval(id);
document.getElementById("skore").innerHTML = "Skore: " + skore;
elem.style.top = '+100%';
}
Working https://jsfiddle.net/ee1bdL5k/
You need declare this var outside from function, for the pric function:
var elem, eleme, elemen;
function naloud() {
elem = document.getElementById("krtek");
elem.style.top = '100%';
eleme = document.getElementById("krtek2");
eleme.style.top = '100%';
elemen = document.getElementById("krtek3");
elemen.style.top = '100%';
}
I'm trying to move the position of a div element at set intervals however the setInterval method executes once and then stops. setInterval() doesn't update .style.transform repeatedly every 200 milliseconds as intended.
<!DOCTYPE html>
<html>
<head>
<title>Snake game</title>
<style type="text/css">
.container {
width: 500px;
height: 500px;
border: 2px solid black;
}
#snakehead {
width: 5px;
height: 5px;
background: pink;
position: relative;
left: 0px;
}
</style>
<script type="text/javascript" src="snake.js"></script>
</head>
<body>
<div class="container">
<div id="snakehead"></div>
</div>
</body>
</html>
Javascript: Ideally I'd also like to be able to move the snakehead in any direction with vx and vy. Anyway to put those values into .style.transform = translateX()?
function snakepos() {
var x = 0;
var y = 0;
var vx = 1;
var vy = 0;
return {
move: function() {
x += vx;
y += vy;
var snakehead = document.querySelector("#snakehead");
snakedhead.style.left = "5px";
}
};
}
window.onload = function() {
console.log("hi");
var container = document.querySelector(".container");
var snake = snakepos();
setInterval(function() {
snake.move();
}, 200);
}
I know this can be done much easier in jQuery with .css but I'd to how this can be done in vanilla javascript. Thank you in advance.
snakehead.style.left = (snakedhead.style.left + "5px");
or
snakehead.style.left = (snakedhead.style.left - "5px");
I'd recommend something in a style a bit more familiar to me:
function snakepos() {
this.x = 0;
this.y = 0;
this.vx = 1;
this.vy = 1;
this.snakehead = document.querySelector("#snakehead");
var me = this;
this.move = function() {
me.x += me.vx;
me.y += me.vy;
me.snakehead.style.top = me.y + "px";
me.snakehead.style.left = me.x + "px";
};
return this;
}
console.log("hi");
var container = document.querySelector(".container");
var snake = new snakepos();
setInterval(function() {
snake.move();
}, 200);
See fiddle: https://jsfiddle.net/theredhead/td8opb0b/1/
I am trying to create new circles as my pen hovers on window.
I am having issues where I cannot add circles to the page. It just hovers around. How would i be able to modify my code to add circles as it hovers.
<!doctype html>
<html>
<head>
<title> JavaScript Environment: Project </title>
<meta charset="utf-8">
<style>
html, body {
width: 100%;
height: 100%;
margin: 0px;
padding: 0px;
}
#canvas {
background-color: yellow;
width: 100%;
height: 100%;
}
.pen {
position: absolute;
background-color: lightblue;
width: 10px;
height: 10px;
border-radius: 5px;
}
</style>
<script>
window.onload = function() {
function Circle(x, y) {
this.x = x;
this.y = y;
}
var canvas = document.getElementById("canvas");
canvas.onmousedown = function() {
mouseDown();
};
canvas.onmouseup = function() {
mouseUp()
};
canvas.onmousemove = function() {
mouseMove(event)
};
function mouseDown (){
console.log ("mouse down");
}
function mouseUp (){
console.log ("mouse up");
}
function mouseMove(e) {
var canvas = document.getElementById("canvas");
var pen = document.createElement("div");
var x = e.clientX;
var y = e.clientY;
var coor = "Coordinates: (" + x + "," + y + ")";
pen.setAttribute("class", "pen");
pen.style.left = x + "px";
pen.style.top = y + "px";
document.getElementById("canvas").innerHTML = coor;
canvas.appendChild(pen);
addCircles(x, y);
console.log("location # " + x + " : " + y);
}
function addCircles(x, y) {
var canvas = document.getElementById("canvas");
var circle = document.createElement("div");
circle.setAttribute("class", "pen");
circle.style.left = x + "px";
circle.style.top = y + "px";
canvas.appendChild(circle);
}
canvas.addEventListener("mouseMove", mouseMove, false);
};
</script>
</head>
<body>
<div id="canvas"></div>
</body>
</html>
The problem is in the line document.getElementById("canvas").innerHTML = coor;
Try adding a span <span id="canvasText"></span> inside of your canvas div and then changing the above line to document.getElementById("canvasText").innerHTML = coor;.
As it stands, you "reset" the contents of the canvas every time the mouse moves, so the circles are instantly removed from it. Reset only the span inside the canvas to keep the circles around.