Adding a class to "body"

drupal drupal-7 drupal-theming

40,026

Solution 1

In your theme's template.php file use the preprocess_html hook:

function mytheme_preprocess_html(&$vars) {
  $vars['classes_array'][] = 'new-class';
}

Remember to clear the caches once you've implemented the hook or Drupal won't pick it up.

Solution 2

The documentation for the html.tpl.php template documents the $classes variables as String of classes that can be used to style contextually through CSS.. If you look at the code for the template, this variable is used in the class attributes of the produced body element:

<body class="<?php print $classes; ?>" <?php print $attributes;?>>

The $classes variables is actually already set by template_process() for any template file and build from the content of the $classes_array variable.

So to add a class to the body of your page, you should add this class to the $classes_array value from your theme (or module)'s implementation of hook_preprocess_html():

function THEME_preprocess_html(&$variables) {
  $variables['classes_array'][] = 'new-class';
}

Since this is the core defined template and process function, any well-behaving theme should re-use the same variables.

Solution 3

I had to use different array keys in the same hook to make it work:

function THEME_preprocess_html(&$vars) {
  $vars['attributes_array']['class'][] = 'foo2';
}

Solution 4

The Context module allows you to add a class to the body tag as well.

This can be useful if you need the class to be added under certain conditions.

You find this options under the reaction "Theme HTML" :

Solution 5

The answer appears to depend on context. Here's what I've found via trial-and-error:

If your hook_preprocess_html() is in a module, use $vars['classes_array'][].

If it's in a theme, use $vars['attributes_array']['class'][].

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40,026

Author by

Chris Muench

Updated on July 12, 2021

Comments

Chris Muench almost 3 years

How can I modify or pre-process the <body> tag to add the class body? I don't want to create a whole html.tpl.php just to add a class.
Chris Muench over 12 years

How does it know to add to body?
Clive over 12 years

There's only one element in html.tpl.php that has any classes added which is the <body> element; the preprocess function above is for that file, so any classes you add will only be added to the <body> element.
Clive over 12 years

By the way, if you haven't already got it install the Devel module and use the dpm function on any variable throughout your code; it will render a nice representation of classes and arrays that are put in the usual message area...it's an absolute must for debugging. You could use it in the above function for example like this: dpm($vars); and it would print the array out to the screen so you can inspect it
nikan about 11 years

I have tried this (cleared cache, checked spelling, etc) and it didn't work. Is there a case that it is affected by another module? I am using context and the omega theme, btw.
Clive almost 11 years

@nikan Probably a bit late now, but for Omega you want to implement mytheme_alpha_preprocess_html and add the class to the $vars['attributes_array']['class'] array
Clive almost 11 years

Not quite - attributes_array is defined specifically by the Omega theme. For 'normal' themes it'll be classes_array
Cloudkiller over 10 years

@Clive thanks for the omega-specific tip, helped me figure out why this answer wasn't working for my site.
nima over 4 years

sometimes it's better to write your answer ( from anywhere ) instead of external links.