Sending PHP Strings Variables to a Javascript String Variables

Question

Hi I am trying to send a long string of numbers from a file to Javascript. One I get it in Javascript as a string the rest will be easy.

This is the PHP code that grabs the series of numbers. It does grab them properly because it prints it out perfectly if I instruct it to do so.

$data = readfile($dataFile);

This is the Javascript Code:

var data = <?php echo json_encode($data, JSON_NUMERIC_CHECK); ?>;

When ever I run it the variable "data" is set to a random number. I assume it is the the number of characters in the sequence. I am relatively new to PHP and Javascript so a nice and clear explanation would be greatly appreciated. Thanks in advance.

JSON is a string, so I suspect no quotes around the PHP output is the issue. — thatidiotguy
– thatidiotguy, Commented Aug 5, 2014 at 17:47

Community · Accepted Answer · 2023-11-17 19:32:19Z

3

Readfile reads the contents of the file and outputs them. It returns the byte length of the file, so $data is the number of the read bytes. link.

edited Nov 17, 2023 at 19:32

CommunityBot

11 silver badge

answered Aug 5, 2014 at 17:47

Michael Wagner

1,0381 gold badge8 silver badges20 bronze badges

Sign up to request clarification or add additional context in comments.

4 Comments

Paul Over a year ago

+1 It would be great if you could show a solution using file_get_contents instead.

Michael Wagner Over a year ago

You want the js-variable data to have the content of the file?

Paul Over a year ago

I believe that is what the OP is expecting

Michael Wagner Over a year ago

Ok, than he has to replace readfile($dataFile) with file_get_contents($dataFile)

Claudio Venturini · Accepted Answer · 2014-08-05 17:49:02Z

1

The number that is set in the variable $data is the number of bytes read by readfile. This is because readfile only reads the file and outputs its content to the standard output. To get the actual data in the file and assign it to a viariable, you can use file_get_contents(), like this:

$data = file_get_contents($dataFile);

Then the javascript assignment is good ;)

answered Aug 5, 2014 at 17:49

Claudio Venturini

6985 silver badges15 bronze badges

Comments

Paul · Accepted Answer · 2014-08-05 17:46:29Z

0

You need quotes if you want it to be a string in Javascript:

var data = '<?php echo json_encode($data, JSON_NUMERIC_CHECK); ?>;';

answered Aug 5, 2014 at 17:46

Paul

142k28 gold badges285 silver badges272 bronze badges

4 Comments

Claudio Venturini Over a year ago

No, you should not add quotes since json_encode adds them automatically if the variable $data is a string. Also, if you add quotes you will have problems if the $data variable contains a string that includes quotes.

Paul Over a year ago

@ClaudioVenturini It doesn't add the quotes with JSON_NUMERIC_CHECK. Try it: echo json_encode('123', JSON_NUMERIC_CHECK); will output 123, not '123'.

Claudio Venturini Over a year ago

Ok, but that it's fine because 123 it's a number, and so it's perfectly valid to assign it to a javascript variable without quotes. If you do json_encode('a_string'), you get "a_string" and not a_string

Paul Over a year ago

@ClaudioVenturini It's valid Javascript to do var data = 123;, but then typeof data will be 'number', and the OP specifically asked for a string in Javascript. I would say that an answer combining our two answers gives the OP exactly what they want.

Collectives™ on Stack Overflow

Sending PHP Strings Variables to a Javascript String Variables

3 Answers 3

4 Comments

Comments

4 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

4 Comments

Comments

4 Comments

Your Answer

Sign up or log in

Post as a guest

Related