print_head_scripts(): string[]
- Since
- 2.8.0
- Source
wp-includes/script-loader.php:2147
Description
Postpones the scripts that were queued for the footer.
print_footer_scripts() is called in the footer to print these scripts.
Compatibility
- WordPress
- since 2.8.0
- PHP
- 7.4–8.6-dev
- 6.7.7
- 6.8.8
- 6.9.7
- 7.0.4
- 7.1.0
Present in every tracked release (6.7.7 to 7.1.0), and compiles on PHP 7.4 through 8.6-dev.
Return value
string[]- Handles of the scripts that were printed.
Performance profile
How much work a call to print_head_scripts() does, and what it touches: the algorithmic scaling, the Zend instruction count per call across PHP versions, the hooks it hands control to, and the core code that calls it. Measured from the compiled opcodes, not a stopwatch, so every number is identical on any machine running the same PHP version, and every function in core is ranked by cost.
- Cost class
- Moderate
- Scaling
- Constant
- Instructions
- 23–28
- Plugin surface
- 2 hooks
- Called by
- 3
Reads stored settings via get_site_option(), cached per request but not free on a cold cache.
No loop in the body: the same number of instructions runs whatever you pass in.
Executed per call on PHP 8.5, depending on the branch taken. The body compiles to 28.
Third-party callbacks on 'wp_print_scripts', 'print_head_scripts' run inside this call, and their cost is not bounded by anything here.
3 places in core call this, so the cost is paid more often than your own code shows.
What it touches
- hookthird-party callbacks
do_action()called directly - optionnetwork option
get_site_option()one call below print_head_scripts()
Further down the call graph this can also reach cache, serialize, query and transient. Those are the worst case, several calls deep and usually down an error path, not what a normal call pays.
What one call costs · 4 distinct outcomes
One number would be a lie: the work depends on which branch runs. These are every distinct cost print_head_scripts() can have, taken from its control-flow graph on PHP 8.5.
| When | Instructions | Calls it makes |
|---|---|---|
did_action() && !apply_filters() | 23 | did_action(), wp_scripts(), script_concat_settings(), ->do_head_items(), apply_filters(), ->reset() |
did_action() && apply_filters() | 25 | did_action(), wp_scripts(), script_concat_settings(), ->do_head_items(), apply_filters(), _print_scripts(), ->reset() |
!did_action() && !apply_filters() | 26 | did_action(), do_action(), wp_scripts(), script_concat_settings(), ->do_head_items(), apply_filters(), ->reset() |
!did_action() && apply_filters() | 28 | did_action(), do_action(), wp_scripts(), script_concat_settings(), ->do_head_items(), apply_filters(), _print_scripts(), ->reset() |
Across PHP versions
Compiles the same on PHP 7.4, 8.1, 8.2, 8.3, 8.4, 8.5 and 8.6-dev: 28 instructions, 23–28 executed per call, 2 branches. The work does not change between versions.
An instruction is not a fixed amount of time, so a matching count is not necessarily the same speed; what it rules out is a difference in the work itself.
Hooks and filters fired · 2
2 hooks fire while print_head_scripts() runs, in this order:
- do_action( wp_print_scripts )actionline 2152 (+5 into the body)
Fires before scripts in the $handles queue are printed.
- apply_filters( print_head_scripts )filterline 2168 (+21 into the body)
Filters whether to print the head scripts.
Uses · 6
- did_action()Retrieves the number of times an action has been fired during the current request.
- do_action()Calls the callback functions that have been added to an action hook.
- wp_scripts()Initializes $wp_scripts if it has not been set.
- script_concat_settings()Determines the concatenation and compression settings for scripts and styles.
- apply_filters()Calls the callback functions that have been added to a filter hook.
- _print_scripts()Prints scripts (internal use only)
Used by · 3
- wp_font_library_render_page()Render the font-library page.
- wp_options_connectors_render_page()Render the options-connectors page.
- wp_print_head_scripts()Prints the script queue in the HTML head on the front end.
Source code
function print_head_scripts() { global $concatenate_scripts; if ( ! did_action( 'wp_print_scripts' ) ) { /** This action is documented in wp-includes/functions.wp-scripts.php */ do_action( 'wp_print_scripts' ); } $wp_scripts = wp_scripts(); script_concat_settings(); $wp_scripts->do_concat = $concatenate_scripts; $wp_scripts->do_head_items(); /** * Filters whether to print the head scripts. * * @since 2.8.0 * * @param bool $print Whether to print the head scripts. Default true. */ if ( apply_filters( 'print_head_scripts', true ) ) { _print_scripts(); } $wp_scripts->reset(); return $wp_scripts->done;}Changelog
Introduced in 2.8.0. One change between 6.7.7 and 7.1.0.
Signature, return type and hooks compared across 5 parsed releases.
array to string[].verified against sourceAbout this page
- Parsed data
- Generated from the wordpress-develop 7.0.4 tag, from
src/wp-includes/script-loader.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it. - Corrections
- Something wrong on this page? Report it and it gets fixed in the next regeneration.