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The following javascript code gives output 6 . How the code is executed? [closed]

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Why the output of the following code is not (1,2,3,4,5)?
var x = 0;
while (x < 6) {
x++;
}
document.write(x);

That is because you are only writing to the document once.
For this, you should probably use a for loop.
for (let x = 0+1; x < 5+1; x++) {
document.write(x);
}
This says x = 0 + 1 = 1 (so it starts at 0), then for every x > 5 + 1 (the +1 is so it ends at 5) do this, then add 1 to x.
Simply: x = 1, then when x is over 5, it will write to the document, then it will add 1 to x to continue the loop.

Each time the loop is repeated, the value in the x variable is updated.
x++ increases the value of x by one unit
And you write the final value

This example shows how to achieve this:
var x = 0;
let myArray = [];
while(x<6) {
++x; // We want x to start at 1
myArray.push(x) // Add the new value of x into the array
}
const string = '(' + myArray.join(',') + ')'; // Format the output string by joining the array in a csv format and wrapping with brackets.
document.write(string);

"X" is not defined - using "For loop" in Javascript [closed]

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I'm currently learning javascript loop and right now i'm trying to make an exemple using the "For" loop but as i'm trying it keep telling me "longString is not defined".
the result i'm trying to have is to print 6 A like this "AAAAAA"
here is the code:
var longString = A;
for (var longString = A; longstring < 6; longString = longString + A) {
console.log(longString);
}
i'm sure the solution is simple but as a totally beginner i can't figure out how to solve it.

You have a typo in your break condition:
var longString = "";
for (longString = "A"; longstring < 6; longString = longString + "A") {
// Note the lowercase 's' ^
}
console.log(longString);
Also, if you want to get the length of a string, you can use string.length:
longString.length < 6;

Does this what you want?
var str = ""
for (i = 0; i < 6; i++) {
str += "A"
}
console.log(str);

Try this, the below code prints "AAAAAA" in one line.
var longString = 'A'
var str = ''
for (var i = 0; i<6; i+=1){
str = longString + str
}
console.log(str)

Questions example phoneNumber [closed]

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I am a student studying JavaScript.
It hasn't been long since I studied.
Example, createPhoneNumber
The length is up to 11 digits.
I wrote the code in question like this.
function createPhoneNumber(arr) {
let first = '(010)';
if(arr.length === 11){
return `(${arr.slice(0,3).join('')})${arr.slice(3,7).join('')}-${arr.slice(7,11).join('')}`;
}
return `${first}${arr.slice(0,4).join('')}-${arr.slice(4,8).join('')}`;
}
I think it's very messy code.
Is it better to add a new variable to make it shorter and simpler?

This can be done by Regex:
function createPhoneNumber(arr) {
let first = '(010)';
// the submatch (\D)? is intended to get an empty match when the length of arr is not 11
let reg = arr.length == 11 ? /(\d{3})(\d{4})(\d{4})/ : /(\D)?(\d{4})(\d{0,4})(\d{0,})/;
return arr.join('').replace(reg, (match, $1, $2, $3) => ($1 ? "(" + $1 + ")" : first) + $2 + "-" + $3);
}
console.log(createPhoneNumber([0,1,0,1,2,3,4,5,6,7,8]));
console.log(createPhoneNumber([1,2,3,4,5,6]));
console.log(createPhoneNumber([1,2,3,4,5,6,7,8,9,0,0,0,0,0]));

You want it shorter and simpler? This is subjective but I believe the following applies. Also, I wasn't sure if you misused your 11th digit in your function so... I made it work with 10.
function createPhoneNumber(arr) {
const arrL = arr.length;
let arrI = arrL - 4;
arr.splice(arrI, 0, "-");
arr.splice(arrI -= 3, 0, ")");
arr.splice(0, 0, arrL === 10 ? "(" : "(010");
return arr.join("");
}

If it's just a matter of readability, I suggest a few changes:
Export hard coded values to const.
Don't duplicate your code! like the complicated return you had.
It did look messy - do I decided to separate the number to 3 parts - 3 variables, and use 1 return
const PRE_FIRST = '(010)';
const FULL_NUMBER_LENGTH = 11;
function createPhoneNumber(arr) {
let isFullPhone = FULL_NUMBER_LENGTH === arr.length;
let first = isFullPhone ? arr.slice(0, 3).join('') : PRE_FIRST;
let second = (isFullPhone ? arr.slice(3, 7) : arr.slice(0, 4)).join('');
let third = (isFullPhone ? arr.slice(7, 11) : arr.slice(4, 8)).join('');
return `${first}-${second}-${third}`;
}

Would like javascript loop [closed]

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I am adding subrows below a main row in an html table depending on which main row button is pushed. Here is some of the code:
if (document.getElementById("hdnSub0")) {
roz0 = document.getElementById("hdnSub0").value || 0;
}
...
if (document.getElementById("hdnSub10")) {
roz10 = document.getElementById("hdnSub10").value || 0;
}
nroz0 = parseInt(roz0, 10);
...
nroz10 = parseInt(roz10, 10);
if (intMainRow == 0) {
i = nroz0 + 2
};
...
if (intMainRow == 10) {
i = nroz0 + 2 + nroz1 + 1 + nroz2 + 1 + nroz3 + 1 + nroz4 + 1 + nroz5 + 1 + nroz6 + 1 + nroz7 + 1 + nroz8 + 1 + nroz9 + 1 + nroz10 + 1
};
row = table.insertRow(i);
I would like to write a loop especially for the if(intMainRow...) but I just haven't been able to it figure out.

So use a loop!
Consider getElementById("hdbSub" + i), where i is the loop variable incremented from 0..10. You can then use the loop (or an intermediate array) to go 0..x depending on the value of intMainRow.
For example:
// Because nroz0 + 2, but nrozOther + 1
// (You could also encode with an if/condition in the loop, but I
// feel like showing it this way.)
var incrs = [2,1,1,1,1,1,1,1,1,1,1];
// Running total (I use i/j/k only for loops.)
var total = 0;
// Will loop [0, intMainRow], an inclusive range, because of "<=".
// We loop once for each "field" and add the result in total.
for (var i = 0; i <= intMainRow; i++) {
var elm = document.getElementById("hdnSub" + i);
if (elm) {
// Add the value to the total along with
// the increment (+2/+1) for this index.
// (Each loop "adds" the next value to the equation
// written manually in the the original code.)
var v = parseInt(elm.value, 10) || 0;
total += v + incrs[i];
}
}
row = table.insertRow(total);

How to convert a string into a series of digits in Javascript? [closed]

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What would be a good way to turn a string into a series of digits in Javascript (I'm not talking about converting "0.5" into 0.5, but more "Hello" into 47392048)?
Any idea appreciated.
Thanks!

You can use the ASCII value of each letter:
"a letter".charCodeAt(0);

Ok, so given your comments, here is a (not widely tested) solution.
var str = "κόσμε 这是一条狗 é €";
$('#orig').after('<dd>' + str + '</dd>');
var result = "";
for (var i = 0, len = str.length, code, paddedCode; i < len; ++i) {
code = str[i].charCodeAt(0).toString();
paddedCode = code.length >= 8
? code
: new Array(8 - code.length + 1).join(0) + code; result += paddedCode;
result += paddedCode;
}
$('#nums').after('<dd>' + result + '</dd>');
var segments = result.match(/.{8}/g);
$.each(segments, function(k, v) {
$('#nums-segmented').after('<dd>' + v + '</dd>');
});
revertedString = '';
for (var i = 0, len = segments.length; i < len; i=i+2) {
revertedString += String.fromCharCode((segments[i] | 0));
}
$('#string').after('<dd>' + revertedString + '</dd>');
Run it at JSFiddle
The trick is to pad number and work with them as string when needed.