Javascript syntax error? [closed] - javascript

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I keep getting a syntax error that I am missing ";" before statement var numDashes += '-';
I am just trying to pass a number to a dashes method and add the respective number of dashes using recursion. Sorry i'm a Java person. Please help.
function dashes(number) {
for (var i=0; i<number; i++){
var numDashes += '-';
}
return numDashes;
}
console.log(dashes(3))

You should declare numDashes first with an empty string.
function dashes(number) {
var numDashes = '';
for (var i=0; i<number; i++){
numDashes += '-';
}
return numDashes;
}

function dashes(number) {
var numDashes = "";
for (var i=0; i<number; i++){
numDashes += '-';
}
return numDashes;
}
console.log(dashes(3))
This should work :) When creating a variable always initialized with something. Otherwise it will be as 'undefined'

Above answer are correct. you can't apply any operation when you define variable. First need to be define variable after that you can implement any operation. So, define "numDashes" variable before loop and than apply "+=" operator in loop.
Correct Syntax:
function dashes(number) {
var numDashes = "";
for (var i=0; i<number; i++){
numDashes += '-';
}
return numDashes;
}
console.log(dashes(3))

Related

Split cookies from page [closed]

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Closed 2 months ago.
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I was doing some coding today, but I got an error:
Cannot read properties of undefined (reading 'split')
at getCookie ((index):38:49)
at (index):47:31
My code (begins at line 36, ends at 43):
var cookieArray = document.cookie.split(";");
for (var i = 0; i < cookieArray.length; i++) {
var cookiePair = cookieArray[1].split("=");
if(name == cookiePair[0].trim()) {
return decodeURIComponent(cookiePair[1])
}
}
Btw, I've read that you can only split a string, but this is a string right?
You should put i instead of 1:
for (var i = 0; i < cookieArray.length; i++) {
var cookiePair = cookieArray[i].split("=");
if(name== cookiePair[0].trim()) {
return decodeURIComponent(cookiePair[i])
}
}
Because the first time it iterates the array cookieArray[1] my be undefind.

Why some parts of this code are red in VS Code? [closed]

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Closed 3 months ago.
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I just started to learn JavaScript. I have this script which should generate composite numbers in my separate HTML file, but I don't really understand why some parts are highlighted red when I moved script to .js file.
So my question is why there are some parts that are highlighted and how I'm suppose to write it correctly? I need to use strict in this script. I know that when using strict mode I need to declare variables, objects etc.
since you are working in a javascript file.
remove the script tags
you only need script tags in other file types like html etc
function checkComposite(num) {
var arr = [];
if( var num == 1 ) {
return false;
}
else if ( var num == 2) {
return false;
}
for (var x = 2; x < num; x++) {
if(num % x == 0) {
return true;
}
}
return false;
}
function compositeNumbers() {
num = Number(document.getElementsById('number').value);
for(var j = 1; j < num; j++) {
if(checkComposite(j)) {
arr.push(j);
}
}
document.getElementsById('result').innerHTML = arr;
}

Accessing An Array from within a function using JavaScript [closed]

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I searched the forum but didn't see a similar question or answer for the question I am about to ask, however if it is duplicated please provide a link and I will view the answer in that post.
Is it possible to access objects in a array from within a closure/ function? I am attempting to do so for the purpose of experimentation.
Here is the code I put together in firebug. I am receive 'undefined'.
var checkers = [1, "string", null];
var i, txt = "";
function myFunction(checkers){
for(var i = 0; i < checkers.length; i++ ){
txt += checkers[i] + " ";
console.log(txt)
}
}
myFunction(checkers);
Absolutely possible, one of JavaScript's strenghts.
Your issue is that you aren't calling your function. Also you don't need a parameter to myFunction since it closes over the context and knows about checkers.
Just delete the paramter and after your code add myFunction() to call it.
var checkers = [1, "string", null];
var i, txt = "";
function myFunction(){
for(var i = 0; i < checkers.length; i++ ){
txt += checkers[i] + " ";
console.log(txt)
}
}
myFunction();
The reason you are getting undefined is because theres not value returned to the console when declaring a function, just like you'd get undefined if you ran:
var t = 'asd'
var checkers = [1, "string", null];
var i, txt = "";
function myFunction(checkers){
for(var i = 0; i < checkers.length; i++ ){
txt += checkers[i] + " ";
console.log(txt)
}
}
myFunction(checkers);
I just ran it and I get:
1
1 string
1 string null
undefined
Since the function doesn't return anything, Firebug displays undefined at the end.

Javascript - Passing from a DOM element to array [closed]

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Closed 8 years ago.
This question was caused by a typo or a problem that can no longer be reproduced. While similar questions may be on-topic here, this one was resolved in a way less likely to help future readers.
Edit the question to include desired behavior, a specific problem or error, and the shortest code necessary to reproduce the problem. This will help others answer the question.
Improve this question
Hello and thank you for your time.
Here is the code :
<script>
var names = document.getElementsByClassName('xx');
var ar = [];
for (var i = 0, c = names.length ; i < c ; i++) {
ar[i] = names[i].innerHTML;
alert(ar[i]);// the results are : undefined
}
</script>`
I've tried to use the method tostring, or to push the results into the array but without success.
Thanks
Your main issue seems to be fixed. Make sure the DOM has been loaded before you try to run your code, and there is no need for two variables in your loop. Simplify it like below:
window.onload = function () {
var names = document.getElementsByClassName('xx');
var ar = [];
for (var i = 0 ; i < names.length ; i++) {
ar[i] = names[i].innerHTML;
alert(ar[i]);
}
};
Fiddle
ar.length equals 0, because you just declare the array, but dont put anything into it. I think what you wanted to do is the following:
var names = document.getElementsByClassName('xx');
var ar = [];
for (var i = 0 ; i < names.length ; i++) {
ar[i] = names[i].innerHTML;
alert(ar[i]);
}

Dont know why this variable will not work [closed]

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Closed 9 years ago.
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I am currently using
var hexArray = ["hexa", "hexb", "hexc", "hexd", "hexe", "hexf", "hexg", "hexh", "hexi", "hexj", "hexk", "hexl", "hexm"];
var burnArray = ["burna", "burnb", "burnc", "burnd", "burne", "burnf", "burng", "burnh", "burni", "burnj", "burnk", "burnl", "burnm"];
for(var i=0; i < hexArray.length; i++){
document.getElementById(hexArray[i]).className='transtart ' + burnArray[i];
};
And this is working just fine, however when I change it to this:
var hexSelect = document.getElementById(hexArray[i]);
var hexArray = ["hexa", "hexb", "hexc", "hexd", "hexe", "hexf", "hexg", "hexh", "hexi", "hexj", "hexk", "hexl", "hexm"];
var burnArray = ["burna", "burnb", "burnc", "burnd", "burne", "burnf", "burng", "burnh", "burni", "burnj", "burnk", "burnl", "burnm"];
for(var i=0; i < hexArray.length; i++){
hexSelect.className='transtart ' + burnArray[i];
};
It no longer works. And I have no idea why.
Look at your top line:
var hexSelect = document.getElementById(hexArray[i]);
It wont compile, because you use the i-variable from the for-loop.
var hexSelect = document.getElementById(hexArray[i]);
var hexArray = ["hexa", "hexb", "hexc", "hexd", "hexe", "hexf", "hexg", "hexh", "hexi", "hexj", "hexk", "hexl", "hexm"];
var burnArray = ["burna", "burnb", "burnc", "burnd", "burne", "burnf", "burng", "burnh", "burni", "burnj", "burnk", "burnl", "burnm"];
for(var i=0; i < hexArray.length; i++){
hexSelect.className='transtart ' + burnArray[i];
};
In the first line of your code you are referencing the hexArray variable which at this point is undefined. The i variable at this point is also undefined.
To get your code working all you need to do is move your first line of code into the first line of the for loop below. Does that work?

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