如何在PHP中声明变量而不在我的html中显示其值？

I am working in a Wordpress website and I need to pass the url of a page as a argument of a function. In this case I am using

bloginfo('url');

to retrieve the base url of the site.

So my code is

<?php 

$portfolio_link = bloginfo('url');

if ( ! function_exists( 'ow_nav' ) ) {
    function ow_nav( $nav_position ) {
        ?>
        <nav id="ow-nav-<?php echo $nav_position; ?>" class="ow-nav clearfix ow-nav-<?php echo $nav_position; ?>">
            <ul class="ow-nav-list">
                <?php ow_nav_item( '#home',         'Home'                ); ?>
                <?php ow_nav_item( '#about',        'About'               ); ?>
                <?php ow_nav_item( '#criteria',     'Investment Criteria' ); ?>
                <?php ow_nav_item( '#approach',     'Approach'            ); ?>
                <?php ow_nav_item( '#team',         'Team'                ); ?>
                <?php ow_nav_item( $portfolio_link, 'Portfolio'           ); ?>
            </ul>
        </nav>
        <?php
    }
}

if ( ! function_exists( 'ow_nav_item' ) ) {
    function ow_nav_item( $link, $text ) {
        ?>
        <li>
            <a href="<?php echo $link; ?>">
                <span class="ow-txt"><?php echo $text; ?></span>
                <span class="ow-dot"></span>
            </a>
        </li>
        <?php
    }
}

But when I do that, that variable gets leaked in my HTML, displaying the url in a random place in the DOM.

Any ideas?

bloginfo() automatically echoes the returned value, as you have seen. To return the value and store it in a variable, you need to use get_bloginfo() instead, e.g.:

$portfolio_link = get_bloginfo('url');

bloginfo ref: https://developer.wordpress.org/reference/functions/bloginfo/
get_bloginfo ref: https://developer.wordpress.org/reference/functions/get_bloginfo/

Note: You will come across many Wordpress functions are like this, where one version will automatically display the value and a second version (usually preceded by get_) return the value e.g. the_title / get_the_title