How do I write array with variable in array in JavaScript

Hi guys,

In PHP, I have an array which look like this:

$arr = ['x' => [$a,$b]];

Code (markup):

How do I write this in JavaScript?

Thanks,

 

Such operations like below seem to be okay in javascript:

var arr = [];
arr['x'] = ['hello', 'world'];

Code (JavaScript):

?
Hendra

 

Hi Hendra,

Thanks. That works.

 

Wooh!

I use it like this:

var xhr = new XMLHttpRequest();
xhr.open('GET', 'index.php?x[0]=' + var_a + '&x[1]=' + var_b, true);
xhr.send();
xhr.onreadystatechange = function () {
    if (xhr.readyState === 4) {
        var msg = JSON.parse(xhr.responseText);
    }
}

Code (markup):

To solve ajax request with link like this:

<a href="index.php?<?php echo http_build_query(['x' => [$a,$b]]); ?>">Get Data</a>

Code (markup):

 

Hey that's new to me; the http_build_query(). Thx .

It seems like you need to process the $arr['x'] in client's browser javascript first before sending the ajax, right? Else, a direct use of the http_build_query() might simplify the steps a bit, I guess:

xhr.open('GET', 'index.php?<?php echo http_build_query(["x" => [$a,$b]]); ?>', true);

PHP:

Hmm, doesn't look nice though

 

It looks nice. With this, you can encrypt data both in PHP and JavaScript, making it harder a bit for hacker to attack.

Ajax can't do something like this if you use the js file:

xhr.open('GET', 'index.php?<?php echo http_build_query(["x" => [$a,$b]]); ?>', true);

Code (markup):

 

Ah, right. I forgot that js should be external whenever possible.

 

No no no, Javascript is not like php, you couldn't use associative array, you should use object.

var arr = {};
arr['x'] = ['hello', 'world'];

Code (JavaScript):

 

My mistake, sorry.
Yes it should be an object.

 

Thanks for pointing that out. I'll go back and have it corrected. Do you have any good links which I can read about? My website is JavaScript heavy, sort of.

 

https://docs.oracle.com/cd/E19957-01/816-6408-10/object.htm#1193229
Beware that ECMA-262 is an old reference. It was the one though which started me to understand objects, arrays and their differences

I'm sure you'll easily find better references, e.g.

• https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array
• https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object

Hendra