generate_navigation_search_output

The generate_navigation_search_output filter allows you to change the HTML markup of your navigation search form.

Usage

WooCommerce Products

For example, if we want our navigation search form to search WooCommerce products:

add_filter( 'generate_navigation_search_output', function() {
    printf(  
        '<form method="get" class="search-form navigation-search" action="%1$s">
            <input type="search" class="search-field" value="%2$s" name="s" title="%3$s" />
            <input type="hidden" name="post_type" value="product" />
        </form>', 
        esc_url( home_url( '/' ) ), 
        esc_attr( get_search_query() ),   
        esc_attr_x( 'Search', 'label', 'generatepress' ) 
    ); 
} );

Posts

If we want our navigation search form to search Posts only:

add_filter( 'generate_navigation_search_output', function() {
    printf(  
        '<form method="get" class="search-form navigation-search" action="%1$s">
            <input type="search" class="search-field" value="%2$s" name="s" title="%3$s" />
            <input type="hidden" name="post_type" value="post" />
        </form>', 
        esc_url( home_url( '/' ) ), 
        esc_attr( get_search_query() ),   
        esc_attr_x( 'Search', 'label', 'generatepress' ) 
    ); 
} );

Add a Placeholder

Or, if you want to add a placeholder to the input:

add_filter( 'generate_navigation_search_output', function() {
    printf(
        '<form method="get" class="search-form navigation-search" action="%1$s">
            <input type="search" placeholder="Enter your search" class="search-field" value="%2$s" name="s" title="%3$s" />
        </form>',
        esc_url( home_url( '/' ) ),
        esc_attr( get_search_query() ),
        esc_attr_x( 'Search', 'label', 'generatepress' ) 
    ); 
} );

Clear Search Field

We can also use the snippet below to clear the search field after search is completed:

add_filter( 'generate_navigation_search_output', function() {
    printf( // WPCS: XSS ok, sanitization ok. 
        '<form method="get" class="search-form navigation-search" action="%1$s"> <input type="search" class="search-field" value="" name="s" title="%2$s" /> </form>', 
        esc_url( home_url( '/' ) ), 
        esc_attr_x( 'Search', 'label', 'generatepress' ) );
} );