I would pass two php variables from a codeigniter controller to a javascript function located to the head of my view. is it possible to do such thing?
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3 Answers
yeah sure, just echo the javascript: <?php echo '<script>var myPhpVariable = "'. $my_var . '";</script>'; ?>
3 Comments
BenOfTheNorth
Remember JS is executed server side from within the HTML document, the PHP is processed before all of that, so you can always print out any JS you need to have done on the fly, as in this answer
BenOfTheNorth
Haha yes, I have no idea why I wrote server side!
Nibhrit
What if i need to pass an entire array, or lets extend it, a multidimensional array... Would this approach work then?
or just set in your controller your variables
eg - in the controller
$data['newvar'] = $myvar_in_the_controller;
and then in the view in the javascript
<?php echo $newvar ?>
Comments
I have been developing a page that requires quite a lot of php data to be ported to the client-side.
I prefer to write DRY code and sought a better way to compose the script instead of line after line of javascript declarations.
Unfortunately, I had to break one of my high-tier coding principles: Never use variable variables". The reasons I don't endorse variable variables are:
- they are harder for future script developers to quickly understand
- they aren't able to enjoy array functions
In the technique to follow, I'll show how to serve up individual javascript declarations in a DRY fashion. I am tolerating the use of a variable variable in this case because it will be clear which variable names are being handled and no array functions will be used. For the record, I never endorse the use of extract() and have never had a good reason to use it in any of my projects. (I am only using extract() to mock the CI behavior.)
PHP: (Demo)
// declared in controller...
$data = [
'a' => -1.5,
'b' => false,
'c' => null,
'd' => 'stringy "string" thing',
'e' => range(3,10),
'f' => "0",
'g' => (object)['food' => 'bard'],
'h' => "not used",
];
// the CodeIgniter effect...
extract($data);
// in your view...
$portToJS = ['a', 'b', 'c', 'd', 'e', 'f', 'g'];
echo "\n<script>\nlet ";
foreach ($portToJS as $i => $variable) {
echo (!$i ? '' : ",\n\t") , "{$variable} = " , json_encode(${$variable});
}
echo ";\n</script>";
Output:
<script>
let a = -1.5,
b = false,
c = null,
d = "stringy \"string\" thing",
e = [3,4,5,6,7,8,9,10],
f = "0",
g = {"food":"bard"};
</script>
It is a good idea to json_encode() your variable values so that you don't need to bother with quoting nor quote escaping.
Ideally, I would prefer to pass a single json_encodeed object, then just access the values from within that structure. However, I have adopted a very heavy project which has been handled by many different developers over the years. Rather than refactor heaps of templates and risk breaking something, I am using the above as a temporary improvement until a proper re-scripting is afforded.
