Generate random string using javascript function

Question

I have the following code within the <script> tags, which are within the <head> tags of my HTML file;

function generateUMR($length = 10) {
    $characters = '0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ';
    $randomString = '';
    for ($i = 0; $i < $length; $i++) {
        $randomString .= $characters[rand(0, strlen($characters) - 1)];
    }
    return $randomString;
}

Within the <body> tags, I have the following line of code in order to output the randomly generated string;

echo '<script type="text/javascript"> generateUMR(); </script>';

I have been trying for a few hours now but I am receiving no output from this code, yet no errors, could someone please tell me where I am going wrong?

Thanks in advance.

In javascript string concatenations is done with + operator, not with . like in php. it should be $randomString += .... also consider declaring the variables with var $characters. If you don't do the variables will go to the global scope which could cause troubles in the future. — Igor Malyk
– Igor Malyk, Commented Jun 25, 2014 at 13:07
@IgorMalyk: That code block is php. (strlen($characters) and the dollar-sign variables are a big hint) — Cerbrus
– Cerbrus, Commented Jun 25, 2014 at 13:09
possible duplicate of Generate a string of 5 random characters in Javascript — Chris Forrence
– Chris Forrence, Commented Jun 25, 2014 at 14:55

MrCode · Accepted Answer · 2014-06-25 13:09:14Z

5

Your function is treated as a string, you need to concatenate the function call like so.

echo '<script type="text/javascript"> ' . generateUMR() . ' </script>';

In order to see the result in the browser, you will need to view the HTML source because the browser won't show the content of a script tag. It doesn't really make sense to output this into a script tag, because it's just a random string, try some other tag such as <p></p> instead.

If you are trying to call the PHP function from the client side, then that won't work. You'll need to use AJAX to do that.

edited Jun 25, 2014 at 13:09

answered Jun 25, 2014 at 13:02

MrCode

64.6k10 gold badges95 silver badges114 bronze badges

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

8 Comments

user3266484 Over a year ago

I altered my code as you suggested but still no output :(

VisioN Over a year ago

... and no one noticed that generateUMR is a PHP function... :)

Reinder Wit Over a year ago

@user3266484 what kind of output are you expecting? your PHP function will just output a random string, no JS logic...

user3266484 Over a year ago

For some reason I can't comment on Reinder Wits comment below, but when I tried his suggestion I got this error - Fatal error: Call to undefined function generateUMR(), any ideas? Thanks for ye're help so far anyway..

user3266484 Over a year ago

I just want it to output the random string so that I can ensure it is working before using in it my furthur code..but it seems the function is outputting nothing?

|

Collectives™ on Stack Overflow

Generate random string using javascript function

1 Answer 1

8 Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

8 Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related