HeadScript Templating Helper
The HeadScript templating helper is an extension of the Placeholder Templating Helper
<script> element is used to either provide inline client-side scripting elements or link to a remote resource
containing client-side scripting code. The HeadScript helper allows you to manage both.
The HeadScript helper supports the following methods for setting and adding scripts:
In the case of the
$src is the remote location of the script to load; this is usually in the form
of a URL or a path. For the
$script is the client-side scripting directives you wish to use in the
Note: Setting Conditional Comments HeadScript allows you to wrap the script tag in conditional comments, which allows you to hide it from specific browsers. To add the conditional tags, pass the conditional value as part of the
$attrsparameter in the method calls.
Example Headscript With Conditional Comments
HeadScript also allows capturing scripts; this can be useful if you want to create the client-side script programmatically, and then place it elsewhere. The usage for this will be showed in an example below.
Finally, you can also use the
headScript() method to quickly add script elements; the signature for this is
headScript($mode = 'FILE', $spec, $placement = 'APPEND'). The
$mode is either
SCRIPT, depending on
if you're linking a script or defining one.
$spec is either the script file to link or the script source itself.
$placement should be either
HeadScript overrides each of
set() to enforce usage of the special methods as listed above.
Internally, it stores each item as a stdClass token, which it later serializes using the
This allows you to perform checks on the items in the stack, and optionally modify these items by simply modifying
the object returned.
Note: Use InlineScript for HTML Body Scripts HeadScript's sibling helper, InlineScript, should be used when you wish to include scripts inline in the HTML body. Placing scripts at the end of your document is a good practice for speeding up delivery of your page, particularly when using 3rd party analytics scripts. Note: Arbitrary Attributes are Disabled by Default By default, HeadScript only will render
You may specify a new script tag at any time. As noted above, these may be links to outside resource files or scripts themselves.
// adding scripts $this->headScript()->appendFile('/js/jquery.js') ->appendScript($onloadScript);
Order is often important with client-side scripting; you may need to ensure that libraries are loaded in a specific order due to dependencies each have; use the various append, prepend, and offsetSet directives to aid in this task:
// Putting scripts in order // place at a particular offset to ensure loaded last $this->headScript()->offsetSetFile(100, '/js/myfuncs.js'); // append uses next index, 101 $this->headScript()->appendFile('/js/jquery-plugin-xyz.js'); // but always have base prototype script load first: $this->headScript()->prependFile('/js/jquery.js');
When you're finally ready to output all scripts in your layout script, simply echo the helper:
<?= echo $this->headScript() ?>
Capturing Scripts Using the HeadScript Helper
Sometimes you need to generate client-side scripts programmatically. While you could use string concatenation, heredocs, and the like, often it's easier just to do so by creating the script and sprinkling in PHP tags. HeadScript lets you do just that, capturing it to the stack:
<?php $this->headScript()->captureStart() ?> var action = '<?php echo $this->baseUrl ?>'; $('#foo_form').attr("action", action); <?php $this->headScript()->captureEnd() ?>
The following assumptions are made:
The script will be appended to the stack. If you wish for it to replace the stack or be added to the top,
you will need to pass
PREPEND, respectively, as the first argument to
The script MIME type is assumed to be
pass it as the second argument to
If you wish to specify any additional attributes for the
<script> tag, pass them in an array as the third