wp_get_loading_attr_default( string $context ): string|bool

Since: 5.9.0
Source: wp-includes/deprecated.php:4703

Gets the default value to use for a loading attribute on an element.

Description

This function should only be called for a tag and context if lazy-loading is generally enabled.

The function usually returns 'lazy', but uses certain heuristics to guess whether the current element is likely to appear above the fold, in which case it returns a boolean false, which will lead to the loading attribute being omitted on the element. The purpose of this refinement is to avoid lazy-loading elements that are within the initial viewport, which can have a negative performance impact.

Under the hood, the function uses wp_increase_content_media_count() every time it is called for an element within the main content. If the element is the very first content element, the loading attribute will be omitted.
This default threshold of 3 content elements to omit the loading attribute for can be customized using the 'wp_omit_loading_attr_threshold' filter.

Compatibility

Deprecated in WordPress 6.3.0. Use wp_get_loading_optimization_attributes() instead.

WordPress: since 5.9.0
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.

Parameters

$contextstring: Context for the element for which the loading attribute value is requested.

Return value

string|bool: The default loading attribute value. Either 'lazy', 'eager', or a boolean false, to indicate that the loading attribute should be skipped.

Performance profile

How much work a call to wp_get_loading_attr_default() 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: Trivial
Scaling: Constant
Instructions: 10–55
Plugin surface: None
Called by: 1

What it touches

hookthird-party callbacksdo_action()one call below wp_get_loading_attr_default()

Further down the call graph this can also reach query, option, cache, serialize 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 · 25 distinct outcomes

One number would be a lie: the work depends on which branch runs. These are every distinct cost wp_get_loading_attr_default() can have, taken from its control-flow graph on PHP 8.5.

When	Instructions	Calls it makes
always	10–22	`_deprecated_function()`
`$context !== "template" && $context !== false`	20–28	`_deprecated_function(), doing_filter()`
`$context !== "template" && $context !== false && $context !== "the_post_thumbnail" && $context !== "wp_get_attachment_image" && is_admin()`	23–25	`_deprecated_function(), is_admin()`
`$context !== "template" && $context !== false && $context !== "the_post_thumbnail" && $context !== "wp_get_attachment_image" && !is_admin() && !in_the_loop()`	26–28	`_deprecated_function(), is_admin(), in_the_loop()`
`$context !== "template" && $context !== false && !doing_filter() && !$wp_query && is_admin()`	27–31	`_deprecated_function(), doing_filter(), is_admin()`
`$context !== "template" && $context !== false && !doing_filter() && $wp_query && !->is_main_query() && $context !== "the_content" && $context !== "the_post_thumbnail"`	29–31	`_deprecated_function(), doing_filter(), ->is_main_query()`
`$context !== "template" && $context !== false && $context !== "the_post_thumbnail" && $context !== "wp_get_attachment_image" && !is_admin() && in_the_loop() && !is_main_query()`	29–31	`_deprecated_function(), is_admin(), in_the_loop(), is_main_query()`
`$context !== "template" && $context !== false && !doing_filter() && !$wp_query && !is_admin() && !in_the_loop()`	30–34	`_deprecated_function(), doing_filter(), is_admin(), in_the_loop()`
`$context !== "template" && $context !== false && !doing_filter() && $wp_query && !->is_main_query() && is_admin()`	30–34	`_deprecated_function(), doing_filter(), ->is_main_query(), is_admin()`
`$context !== "template" && $context !== false && !doing_filter() && $wp_query && ->is_main_query() && !did_action() && $context !== "the_content" && $context !== "the_post_thumbnail"`	33–35	`_deprecated_function(), doing_filter(), ->is_main_query(), did_action()`
`$context !== "template" && $context !== false && !doing_filter() && !$wp_query && !is_admin() && in_the_loop() && !is_main_query()`	33–37	`_deprecated_function(), doing_filter(), is_admin(), in_the_loop(), is_main_query()`
`$context !== "template" && $context !== false && !doing_filter() && $wp_query && !->is_main_query() && !is_admin() && !in_the_loop()`	33–37	`_deprecated_function(), doing_filter(), ->is_main_query(), is_admin(), in_the_loop()`

13 further outcomes, up to 55 instructions

`$context !== "template" && $context !== false && !doing_filter() && $wp_query && ->is_main_query() && did_action()`	33–39	`_deprecated_function(), doing_filter(), ->is_main_query(), did_action(), did_action()`
`$context !== "template" && $context !== false && !doing_filter() && $wp_query && ->is_main_query() && !did_action() && is_admin()`	34–38	`_deprecated_function(), doing_filter(), ->is_main_query(), did_action(), is_admin()`
`$context !== "template" && $context !== false && !doing_filter() && $wp_query && !->is_main_query() && !is_admin() && in_the_loop() && !is_main_query()`	36–40	`_deprecated_function(), doing_filter(), ->is_main_query(), is_admin(), in_the_loop(), is_main_query()`
`$context !== "template" && $context !== false && $context !== "the_post_thumbnail" && $context !== "wp_get_attachment_image" && !is_admin() && in_the_loop() && is_main_query()`	36–38	`_deprecated_function(), is_admin(), in_the_loop(), is_main_query(), wp_increase_content_media_count(), wp_omit_loading_attr_threshold()`
`$context !== "template" && $context !== false && !doing_filter() && $wp_query && ->is_main_query() && !did_action() && !is_admin() && !in_the_loop()`	37–41	`_deprecated_function(), doing_filter(), ->is_main_query(), did_action(), is_admin(), in_the_loop()`
`$context !== "template" && $context !== false && !doing_filter() && $wp_query && ->is_main_query() && did_action() && is_admin()`	38–42	`_deprecated_function(), doing_filter(), ->is_main_query(), did_action(), did_action(), is_admin()`
`$context !== "template" && $context !== false && !doing_filter() && !$wp_query && !is_admin() && in_the_loop() && is_main_query()`	40–44	`_deprecated_function(), doing_filter(), is_admin(), in_the_loop(), is_main_query(), wp_increase_content_media_count(), wp_omit_loading_attr_threshold()`
`$context !== "template" && $context !== false && !doing_filter() && $wp_query && ->is_main_query() && !did_action() && !is_admin() && in_the_loop() && !is_main_query()`	40–44	`_deprecated_function(), doing_filter(), ->is_main_query(), did_action(), is_admin(), in_the_loop(), is_main_query()`
`$context !== "template" && $context !== false && !doing_filter() && $wp_query && ->is_main_query() && did_action() && !is_admin() && !in_the_loop()`	41–45	`_deprecated_function(), doing_filter(), ->is_main_query(), did_action(), did_action(), is_admin(), in_the_loop()`
`$context !== "template" && $context !== false && !doing_filter() && $wp_query && !->is_main_query() && !is_admin() && in_the_loop() && is_main_query()`	43–47	`_deprecated_function(), doing_filter(), ->is_main_query(), is_admin(), in_the_loop(), is_main_query(), wp_increase_content_media_count(), wp_omit_loading_attr_threshold()`
`$context !== "template" && $context !== false && !doing_filter() && $wp_query && ->is_main_query() && did_action() && !is_admin() && in_the_loop() && !is_main_query()`	44–48	`_deprecated_function(), doing_filter(), ->is_main_query(), did_action(), did_action(), is_admin(), in_the_loop(), is_main_query()`
`$context !== "template" && $context !== false && !doing_filter() && $wp_query && ->is_main_query() && !did_action() && !is_admin() && in_the_loop() && is_main_query()`	47–51	`_deprecated_function(), doing_filter(), ->is_main_query(), did_action(), is_admin(), in_the_loop(), is_main_query(), wp_increase_content_media_count(), wp_omit_loading_attr_threshold()`
`$context !== "template" && $context !== false && !doing_filter() && $wp_query && ->is_main_query() && did_action() && !is_admin() && in_the_loop() && is_main_query()`	51–55	`_deprecated_function(), doing_filter(), ->is_main_query(), did_action(), did_action(), is_admin(), in_the_loop(), is_main_query(), wp_increase_content_media_count(), wp_omit_loading_attr_threshold()`

Across PHP versions

Compiles the same on PHP 7.4, 8.1, 8.2, 8.3, 8.4, 8.5 and 8.6-dev: 62 instructions, 10–55 executed per call, 15 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.

Uses · 8

_deprecated_function()Marks a function as deprecated and inform when it has been used.
doing_filter()Returns whether or not a filter hook is currently being processed.
did_action()Retrieves the number of times an action has been fired during the current request.
is_admin()Determines whether the current request is for an administrative interface page.
in_the_loop()Determines whether the caller is in the Loop.
is_main_query()Determines whether the query is the main query.
wp_increase_content_media_count()Increases an internal content media count variable.
wp_omit_loading_attr_threshold()Gets the threshold for how many of the first content media elements to not lazy-load.

Used by · 1

wp_img_tag_add_loading_attr()Adds `loading` attribute to an `img` HTML tag.

Changelog

Introduced in 5.9.0. Unchanged from 6.7.7 through 7.1.0.

Signature, return type and hooks compared across 5 parsed releases.

6.3.0

Deprecated. Use wp_get_loading_optimization_attributes() instead.from the docblock

5.9.0

Introduced.from the docblock

About this page

Parsed data: Generated from the wordpress-develop 7.1.0 tag, from src/wp-includes/deprecated.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.