Javascript/Dom loading images in to grid

Javascript/Dom loading images in to grid - javascript

I'm pretty new to programming and javascript/dom. Ultimately, I'm trying to make a sliding puzzle game but to start off with, I'm just trying to get the images loading up in a random order. It's going to be a 4x4 grid of images. The images are named Tree00, 01, 02, 03, 10, etc up to 33. Here's my code so far:
<html>
<head>
<title>Shuffle</title>
</head>
<body>
<script language="JavaScript">
<!--
Pics = new Array();
var Top = 16;
for(i = 0; i < Top; i++) {
document.write("<img><img><img><img><br>");
}
function RandomInt(Min, Max) {
RI = Math.floor(Math.random() * (Max - Min + 1)) + Min;
return(RI);
}
function Shuffle() {
N = RandomInt(0, 1);
this.Image.src=Pics[N];
this.Image.style.left = 220;
}
function ViewerObj(Image, Pics, i) {
this.Image = Image;
this.Image.style.left = 800;
this.Pics = Pics;
this.Shuffle = Shuffle;
this.Image.id = "ID" + i;
}
function Randomise() {
var i;
for(i = 0; i < Top; i++) {
Viewers[i].Shuffle();
Viewers[i].Image.style.left = 200;
}
}
Viewers = new Array();
var i;
for(i = 0; i < 3; i++) {
Pics[i] = "images/Tree" + (i) + (i + 1) + ".jpg";
}
for(i = 0; i < Top; i++) {
document.images[i].src = "images/Blank.jpg";
document.images[i].style.left = 300;
Viewers[i] = new ViewerObj(document.images[i], Pics, i);
}
//-->
</script>
<h1>Shuffle</h1>
<form>
<input type="button" value="Shuffle" onClick="Randomise();"/>
</form>
</body>
</html>
I just can't quite fathom what I need to be changing and how I'd go about it. Any help + explanation would be much appreciated. What I am trying to achieve is it loading every image but just in a random order, but with no duplicates.

Here are a few problems in your script :
first replace
for(i = 0; i < Top; i++) {
document.write("<img><img><img><img><br>");
}
by
for(i = 0; i < Top; i++) {
document.write("<img>");
if ((i+1)%4 == 0) {
document.write("<br>");
}
}
you will get only 16 IMG elements instead of 4*16 in your code
then you will need 16 different names for your images : replace
for(i = 0; i < 3; i++) {
Pics[i] = "images/Tree" + (i) + (i + 1) + ".jpg";
}
by
for(var i = 0; i < 4; i++) {
for(var j = 0; j < 4; j++) {
Pics[j+4*i] = "images/Tree" + (i) + (j) + ".jpg";
}
}
Then you biggest problem is the shuffling. You cannot shuffle the "Viewers" one-by-one because you want to avoid duplicates. Each viewer must randomly select a unique image.
For this you can use the technique in mdarwi's answer : shuffle the Pics table for instance.
check your modified code on jsbin here

If your problem is simply that you'd like the images to be properly shuffled, you can use the following code (taken directly from the Javascript sample code for the Fisher-Yates shuffle on Wikipedia:
var n = a.length;
for(var i = n - 1; i > 0; i--) {
var j = Math.floor(Math.random() * (i + 1));
var tmp = a[i];
a[i] = a[j];
a[j] = tmp;
}
The easiest thing to do would be to rename your images Tree1 to TreeN, and then place N integers in an array and shuffle them using the above algorithm.

(This is a code-comment, not an answer)
Pics = new Array();
The Pics variable should be declared before using. Also, use the shorthand notation []
var Pics = [];
var Top = 16;
for (i = 0; i < Top; i++) {
document.write("<img><img><img><img><br>");
}
The i variable is declared only later in the code. It should be declared at the top of the program.
function RandomInt(Min, Max) {
RI = Math.floor(Math.random() * (Max - Min + 1)) + Min;
return (RI);
}
This is particularly dangerous: the RI variable is not declared inside the function, so it becomes an implicit global property. That should be avoided. Also, the parens in the return statement are superfluous.
function RandomInt(Min, Max) {
return Math.floor(Math.random() * (Max - Min + 1)) + Min;
}
function Shuffle() {
N = RandomInt(0, 1);
this.Image.src = Pics[N];
this.Image.style.left = 220;
}
Again, the N variable should be declared. Also, why is this "method" declared outside of the ViewerObj constructor? Either, put it inside, or - even better - add it to the constructors prototype object. That way, there will only be one Shuffle function object instead of many.
function ViewerObj(Image, Pics, i) {
this.Image = Image;
this.Image.style.left = 800;
this.Pics = Pics;
this.Shuffle = Shuffle;
this.Image.id = "ID" + i;
}
function Randomise() {
var i;
for (i = 0; i < Top; i++) {
Viewers[i].Shuffle();
Viewers[i].Image.style.left = 200;
}
}
Viewers = new Array();
var i;
As mentioned above, the i variable should be declared on top. Also, the Viewers variable should be declared.
var Viewers = [];
for (i = 0; i < 3; i++) {
Pics[i] = "images/Tree" + (i) + (i + 1) + ".jpg";
}
for (i = 0; i < Top; i++) {
document.images[i].src = "images/Blank.jpg";
document.images[i].style.left = 300;
Viewers[i] = new ViewerObj(document.images[i], Pics, i);
}

Related

Randomize and show a given number if elements on pageload

I want to randomize elements on pageload - and just show 4 of them regardless on how many there are.
The closest I come is this:
$(document).ready(function() {
$(".itembox.newcenterbox").hide();
var elements = $(".itembox.newcenterbox");
var elementCount = elements.size();
var elementsToShow = 4;
var alreadyChoosen = ",";
var i = 0;
while (i < elementsToShow) {
var rand = Math.floor(Math.random() * elementCount);
if (alreadyChoosen.indexOf("," + rand + ",") < 0) {
alreadyChoosen += rand + ",";
elements.eq(rand).show();
++i;
}
}
});
It works for me on my local site - but it chrashes my live site.and I can't figure out why.
Is there a better way to do this?

Maybe your elementCount is less than elementsToShow? In this case, you will always get rand value between 0 and 3, and it will lead to an infinite loop.
Try the code below. Also I removed unnecessary loop iterations when you check the rand index.
$(document).ready(function() {
var elements = $(".itembox.newcenterbox");
var elementsToShow = 4;
var i = 0;
if(elements.length < elementsToShow) return;
for (i = 0; i < elementsToShow; i++) {
elements.splice(Math.floor(Math.random() * elements.length), 1);
}
elements.hide();
});

Javascript syntax issue in code

Can someone tell me why this bit of JavaScript is buggy?
I have HTML also, but I don't want to make this a massive code dump.
<script type = 'text/javascript'>
var playerCards = [];
var dealerCards = [];
function deal() {
var newCard = Math.random() % 12;
var newCard2 = Math.random() % 12;
playerCards += newCard;
playerCards += newCard2;
var counter = 0;
for (var i = 0; i < playerCards.length; ++i) {
counter += i;
}
document.getElementById("playerTotal").innerHTML = counter;
var dCounter = 0;
for (var j = 0; j < playerCards.length; ++j) {
dCounter += j;
}
document.getElementById("dealerTotal").innerHTML = dCounter;
}
</script>
I'm gonna assume this is a silly syntax error someplace, but I can't find it.

I'm guessing that this isn't doing what you expect it to:
playerCards += newCard;
playerCards += newCard2;
Try this instead:
playerCards.push(newCard);
playerCards.push(newCard2);
The first snippet is trying to "add" a number to an array, which doesn't exactly make sense. Through some arcane JavaScript rules, this turns the result into a string.
I'm guessing that you want to concatenate to an array instead.

Math.random returns a number between 0 and 1 - so Math.random() % 12 will probably be zero
var playerCards = [];
playerCards += newCard; //
what are you even trying to do there?
var counter = 0;
for (var i = 0; i < playerCards.length; ++i) {
counter += i;
}
if playerCards had a length, this loop would result in counter having value of 0, 1, 3, 6, 10 .. n(n+1) / 2 - probably not what you intended, but who knows

Filling up a 2D array with random numbers in javascript

I'm really sorry if anything like this has been posted here before but I couldn't find anything, I'm kinda new to the site still!
So for a while now I've been learning a bit about game development through html5 and javascript and I stumbled upon making tileset maps, I now have a tileset and an 2D array that I want to put certain tiles in (the number varies between 6 and 10 in this case).
I figured it could be a cool function to make the map choose between a small set of similar tiles so I don't have to specifically number every tile in the array(just define the type)
The method I have currently is probably the best for being able to define types but I want something that looks a bit cleaner and/or information to why my "cleaner" version dosen't work.
var ground = [
[tile(),tile(),tile(),tile(),tile(),tile(),tile(),tile(),tile(),tile(),tile(),tile(),tile(),tile(),tile()],
[tile(),tile(),tile(),tile(),tile(),tile(),tile(),tile(),tile(),tile(),tile(),tile(),tile(),tile(),tile()],
[tile(),tile(),tile(),tile(),tile(),tile(),tile(),tile(),tile(),tile(),tile(),tile(),tile(),tile(),tile()],
[tile(),tile(),tile(),tile(),tile(),tile(),tile(),tile(),tile(),tile(),tile(),tile(),tile(),tile(),tile()],
[tile(),tile(),tile(),tile(),tile(),tile(),tile(),tile(),tile(),tile(),tile(),tile(),tile(),tile(),tile()],
[tile(),tile(),tile(),tile(),tile(),tile(),tile(),tile(),tile(),tile(),tile(),tile(),tile(),tile(),tile()],
[tile(),tile(),tile(),tile(),tile(),tile(),tile(),tile(),tile(),tile(),tile(),tile(),tile(),tile(),tile()],
[tile(),tile(),tile(),tile(),tile(),tile(),tile(),tile(),tile(),tile(),tile(),tile(),tile(),tile(),tile()],
[tile(),tile(),tile(),tile(),tile(),tile(),tile(),tile(),tile(),tile(),tile(),tile(),tile(),tile(),tile()]];
function tile() {
var y = (Math.random() * 5 | 0) + 6;
return y;
}
This is the code I've been using so far, I have to edit every element of the code with the tile() function to get a random number in each one, what I wanted to have was something like this:
for (var i = 0 ; i < 15; i++) {
for (var j = 0; j < 9; j++) {
ground[[i],[j]] = (Math.random() * 5 | 0) + 6;
}
}
to fill the array without having to add the function to each spot.
I have a feeling that I'm missing a return function or something along those lines but honestly I have no idea.

You were thinking in the right direction but there are some errors in your code ;)
You have to initialize the array first before you can push elements into it.
And you were counting i++ twice
Javascript
var ground = []; // Initialize array
for (var i = 0 ; i < 15; i++) {
ground[i] = []; // Initialize inner array
for (var j = 0; j < 9; j++) { // i++ needs to be j++
ground[i][j] = (Math.random() * 5 | 0) + 6;
}
}
Maybe even better (reusable)
function createGround(width, height){
var result = [];
for (var i = 0 ; i < width; i++) {
result[i] = [];
for (var j = 0; j < height; j++) {
result[i][j] = (Math.random() * 5 | 0) + 6;
}
}
return result;
}
// Create a new ground with width = 15 & height = 9
var ground = createGround(15, 9);

Here's a quick example. I've created a function that will take in a width and height parameter and generate the size requested. Also I placed your tile function inside generate ground to keep it private, preventing other script from invoking it.
var ground = generateGround(10, 10); //Simple usage
function generateGround(height, width)
{
var ground = [];
for (var y = 0 ; y < height; y++)
{
ground[y] = [];
for (var x = 0; x < width; x++)
{
ground[y][x] = tile();
}
}
return ground;
function tile()
{
return (Math.random() * 5 | 0) + 6;
}
}
http://jsbin.com/sukoyute/1/edit

Try removing the comma from...
ground[[i],[j]] = (Math.random() * 5 | 0) + 6;
...in your 'clean' version. Also, your incrementing 'i' in both for loops:
for (var i = 0 ; i < 15; i++) {
for (var j = 0; j < 9; i++) {
Hopefully these changes make it work for you :)

2D array improperly filled and undefined in JavaScript

I am writing a function with two sub-functions: one to print a 2D array from two values in the form and the other to print out the 2D array. At this point, I have been trying to use variables with integer values to fill in the 2D array, but they are not being filled properly. The min variable seems to have the value of 0 within the function instead of what is being passed.
Anyways after I create the 2D array, I try to test print the 2D array 'twoDarray', but it comes up as undefined?
function isValid(frm) {
var xValue = document.getElementById("X").value;
var yValue = document.getElementById("Y").value;
if (xValue <= yValue)
{
/* Draw out the multiplication table. */
function gen2Darray(min, max)
{
var lengthOf2Darray = (max - min);
var twoDarray = new Array(lengthOf2Darray);
for (var i = 0; i < lengthOf2Darray; i++)
{
twoDarray[i] = new Array(lengthOf2Darray);
for (var j = 0; j < lengthOf2Darray; j++)
{
twoDarray[i][j] = ((min + i) * (min + j)); // only takes i
}
}
}
gen2Darray(xValue, yValue);
function print_2d_string_array (array)
{
// print twoDarray, but twoDarray undefined here
}
I have created a jsfiddle account, but it does not work the same way on the site: http://jsfiddle.net/imparante/5yTEv/.
Fix:
function isValid(frm) {
var xValue = document.getElementById("X").value;
var yValue = document.getElementById("Y").value;
var lengthOf2Darray = (yValue - xValue);
var twoDarray = new Array(lengthOf2Darray);
if (xValue <= yValue) {
/* Draw out the multiplication table. */
function gen2Darray(min, max) {
// var lengthOf2Darray = (max - min);
// var twoDarray = new Array(lengthOf2Darray);
for (var i = 0; i < lengthOf2Darray; i++) {
twoDarray[i] = new Array(lengthOf2Darray);
for (var j = 0; j < lengthOf2Darray; j++) {
twoDarray[i][j] = ((min + i) * (min + j));
$("#table").append(twoDarray[i][j] + " ");
}
}
return twoDarray;
}
gen2Darray(xValue, yValue);
function print_2d_string_array(array){
// print twoDarray
}

You're getting undefined on twoDarray because the array is declared and created inside gen2Darray() but you are trying to access it from print_2d_string_array().
If you move your var twoDarray = new Array(); up to you xValue and yValue declarations that should solve the undefined error.
Bin example
function isValid(frm) {
var xValue = document.getElementById("X").value;
var yValue = document.getElementById("Y").value;
var lengthOf2Darray;
var twoDarray = [];
if (xValue <= yValue){
/* Draw out the multiplication table. */
gen2Darray(xValue, yValue);
print_2d_string_array(twoDarray);
}
function gen2Darray(min, max){
lengthOf2Darray = (max - min);
twoDarray = [lengthOf2Darray];
for (var i = 0; i < lengthOf2Darray; i++){
twoDarray[i] = new Array(lengthOf2Darray);
for (var j = 0; j < lengthOf2Darray; j++){
twoDarray[i][j] = ((min + i) * (min + j)); // only takes i
}
}
}
function print_2d_string_array(array){
console.log(array);
}
}

The declarating of the functions were a bit wrong, also the function gen2Darray was not actually returning anything, so the variable twoDarray would only be available in the scope of the function.
Please see fixed code here: http://jsfiddle.net/CC5vP/
I moved the two functions out of the main function declaration and then added a return in gen2Darray(min, max)
It appears to be working, you will want to modify print_2d_string_array(a) to display the data instead of logging it to the console.

JavaScript syntax issue

I'm doing "fifteen puzzle" game. I'm only a beginner, so I chose this project to implement. My problem is shuffle algorithm :
function shuffle() {
$('td').empty();
var p = 0;
var f = 0;
do {
var arr = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15];
var rand = arr[Math.floor(Math.random() * arr.length)];
if ($('#' + rand).is(':empty')) {
p = p + 1;
document.getElementById(rand).textContent = p
var f = $('td').not(":empty").length;
} else {}
} while (f < 15)
That works cool, but I've heard that almost 50% of all random shuffle like mine is unsolvable. So I found math formula at wikipedia.org for this game, explaining how you can avoid that.
Here's modified algorithm that doesn't work either. The way I know it is alert stuff: it launches only 2 times instead of 31.
array = [];
function algorithm (){
// alert('works')
for (var c=16; c<17; c++){
document.getElementById(c).textContent = '100';
}
for (var i=1; i<16; i++){
var curId = document.getElementById(i).id;
var curIdNum = Math.floor(curId);
alert('works')
var curIn = document.getElementById(i).textContent;
var curInNum = Math.floor(curIn);
array.push(i);
array[i] = new Array();
for (var j=1; j<15; j++){
var nextId = curIdNum + j; //curIdNum NOT cerIdNum
var nextIn = document.getElementById(nextId).textContent;
//alert('works')
if (nextId < 16){
var nextInNum = Math.floor(nextIn);
if (curInNum > nextInNum){
array[i].push(j)
}
}
}
var sum = 0;
for (var a=0; a<15; a++){
var add = array[a].length;
sum = sum + add;
}
var end = sum + 4;
if (end % 2 == 0){
document.getElementById('16').textContent = "";
}
else {
shuffle();
}
}
}
The question is the same:
What's wrong? Two-dimensional array doesn't work.If you've got any questions - ask.
Just to make it clear: 2 for loops with i and j should make a 2-dimensional array like this [ this is " var i" -->[1,3,4,5,7], this is "var i" too-->[5,7,9,14,15]]. Inside each i there's j. The for loop with var a should count the number of js inside each i. if the number of js is even, the code is finished and shuffle's accomplished, otherwise shuffle should be made once again.

var nextId = cerIdNum + j;
in that fiddle, I don't see this cerIdNum declared & defined neither as local nor as global variable, I suppose that is curIdNum

Please use the below definition of algorithm and let us know if this works. Basically, the alert messages would come only twice, since there were usages of undefined variables. For the purpose of illustration, I have placed comments at where the problem points occured. Due to these problems, your script would stop executing abruptly thereby resulting in the behavior you described.
Oh and by the way - I did not have time to go through the Wiki link provided - hence you will have to verify your logic is correct. However, I have definitely resolved the errors causing the behavior you observed.
As an aside - consider using jQuery, your code will be a lot cleaner...
function algorithm (){
// alert('works')
for (var c=16; c<17; c++){
document.getElementById(c).textContent = '100';
}
for (var i=1; i<16; i++){
var curId = document.getElementById(i).id;
var curIdNum = Math.floor(curId);
alert('works')
var curIn = document.getElementById(i).textContent;
var curInNum = Math.floor(curIn);
array.push(i);
for (var j=1; j<15; j++){
var nextId = curIdNum + j; //curIdNum NOT cerIdNum
var nextIn = document.getElementById(nextId).textContent;
//alert('works')
if (nextId < 16){
var nextInNum = Math.floor(nextIn);
if (curInNum > nextInNum){
array.push(j) //array[i].push does not make sense
}
}
}
var sum = 0;
for (var a=0; a<15; a++){
var add = array.length; //array[1].length does not make sense
sum = sum + add;
}
var end = sum + 4;
if (end % 2 == 0){
document.getElementById('16').textContent = "";
}
else {
shuffle();
}
}
}

I found the solution by totally rewriting the code. Thank everyone for help!
Here's what do work:
function shuffle (){
press = 1;
$('td').empty().removeClass();
p=0;
var f;
do {
var arr=[1,2,3,4,5,6,7,8,9,10,11,12,13,14,15];
var rand=arr[Math.floor(Math.random()*arr.length)];
if ($('#'+ rand).is(':empty')){
p = p + 1;
document.getElementById(rand).textContent = p
var f = $('td').not(":empty").length;
}
else{}
}while(f < 15){
winChance();
}
}
function winChance (){
array = [];
for (i=1;i<16;i++){
array[i]= new Array();
var currentId = $('#' + i).attr('id');
var currentIn = $('#' + i).html()
var currentIdNum = parseInt(currentId, 10);
var currentInNum = parseInt(currentIn, 10);
for (j=1;j<16;j++){
var nextId = currentIdNum + j;
if (nextId < 16){
var nextIn = $('#' + nextId).html();
var nextInNum = parseInt(nextIn, 10);
if (currentInNum > nextInNum){
array[i].push(j);
}
}
}
}
checkSum();
}
function checkSum(){
var sum = 0;
for (var a=1; a<16; a++){
var add = array[a].length;
sum = sum + add;
}
var end = sum + 4;
if (end % 2 == 0){}
else {
shuffle();
}
}

Develop Reference

JavaScript is the programming language of the Web.

Javascript/Dom loading images in to grid - javascript

Related

Randomize and show a given number if elements on pageload

Javascript syntax issue in code

Filling up a 2D array with random numbers in javascript

2D array improperly filled and undefined in JavaScript

JavaScript syntax issue

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