如何使用php自动将css类应用于特定单词[关闭]

Basically, I have two words in every posts of my content, they are "Preview" and "Download". I want to apply an css class to style these two words as buttons. I can do it post by post, but it takes a lot of time and I think there should be a way to do it with coding.

I am using wordpress and can it be done using PHP? or any help or suggestion for this?

Thanks in advance guys!

$html=str_replace("Preview","<span class=\"AnyClass\">Preview</span>",$html);

And same for your other marker

$html=str_replace("Download","<span class=\"AnyClass\">Download</span>",$html);

Add this to your function.php

function replace_content($content)
{
    $content = str_replace("Preview","<span class=\"AnyClass\">Preview</span>",$content);
    $content = str_replace("Download","<span class=\"AnyClass\">Download</span>",$content);
    return $content;
}
add_filter('the_content','replace_content');

// string
$str = 'Hello Preview and Download where are you?';

// Regex
echo preg_replace('/(Preview|Download)/im', '<span class="myclass">$1</span>', $str);

Output

Hello <span class="myclass">Preview</span> and <span class="myclass">Download</span> where are you?