Flowdock
content_tag(name, content_or_options_with_block = nil, options = nil, escape = true, &block) public

Returns an HTML block tag of type name surrounding the content. Add HTML attributes by passing an attributes hash to options. Instead of passing the content as an argument, you can also use a block in which case, you pass your options as the second parameter. Set escape to false to disable attribute value escaping.

Options

The options hash is used with attributes with no value like (disabled and readonly), which you can give a value of true in the options hash. You can use symbols or strings for the attribute names.

Examples

  content_tag(:p, "Hello world!")
   # => <p>Hello world!</p>
  content_tag(:div, content_tag(:p, "Hello world!"), :class => "strong")
   # => <div class="strong"><p>Hello world!</p></div>
  content_tag("select", options, :multiple => true)
   # => <select multiple="multiple">...options...</select>

  <%= content_tag :div, :class => "strong" do -%>
    Hello world!
  <% end -%>
   # => <div class="strong">Hello world!</div>
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June 20, 2008
13 thanks

Nil V.S. Empty String HTML Options

There is a difference between an empty string and nil value for options hash.

Code Sample

content_tag( :div, 'Hello World!', :class=>'') # => "<div class="">Hello World!</div>"
content_tag( :div, 'Hello World!', :class=>nil) # => "<div>Hello World!</div>"
February 17, 2009
9 thanks

Empty elements

If you want to output an empty element (self-closed) like “br”, “img” or “input”, use the tag method instead.

August 14, 2008
6 thanks

Optional classes

This piece of syntax saves me allot of time. Note the if statement.

Code example

content_tag(:div, "Hello World", :class => ("active" if i_am_an_active_item?))
May 23, 2011 - (>= v3.0.5)
5 thanks

Change to the way the block is handled

At least in 3.0.5, some of the previous examples no longer work: ActionView seems to quietly ignore Array content.

If you were using code of the form

content_tag(:li, nil, :class => 'someClass') {
  arr.collect { |x|
    content_tag(:ul, x)
  }
}

it now needs to look like

content_tag(:li, nil, :class => 'someClass') {
  arr.reduce('') { |c, x|
    c << content_tag(:ul, x)
  }.html_safe
}
January 27, 2009
5 thanks

Use collect in nested content_tags

Remember to use #collect instead of #each in nested content_tags

arr = ['a','b','c']
content_tag :div do 
  arr.collect { |letter| content_tag(:scan, letter) 
end
#=> <div>
#      <scan>a</scan>
#      <scan>b</scan>
#      <scan>c</scan>
#   </div>

If you used #each you would get this (which is probably a mistake):

#=> <div>
#      abc
#   </div>
March 24, 2009
2 thanks

Content_tag in helpers

Content_tag works great in a helper and is a nice way to clean up your views.

If you’re returning more than one content_tag you’ll need to concat them:

@content = content_tag(:tr, "first item")
@content << content_tag(:tr, "second item")

Be mindful that when doing the above, you must use parentheses around the content_tag options. In the above example, content_tag :tr, “second item” will return an error.

February 15, 2009
0 thanks

use #collect instead of #each

The earlier reminder to use #collect instead of #each applies regardless of whether the tag is nested or not.

This is counterintuitive, as #collect returns an array of strings of HTML tags, but ActionView renders it properly.

November 24, 2012 - (v3.0.5 - v3.2.8)
0 thanks

Use collect instead of inject/reduce

You can still use collect when you nest content_tag . Just join the collection in the end and remember to add html_safe if you don’t want your html to be escaped.

a = ['a','b','c']
content_tag(:ul, :class => 'a class') do
  a.collect do |item|
    content_tag(:li, item)
  end.join.html_safe
end
April 2, 2013 - (v3.0.0 - v3.2.13)
0 thanks

Use concat insted of joining collection explicitely

concat method will be useful to join the collection object from looping conditions.

arr = ["a", "b", "c"]
content_tag(:ul, :class => 'a class') do
  arr.each do |item|
  concat content_tag(:li, item)
end

And this will generate the html as shown below

<ul class="a class">
  <li>a</li>
  <li>b</li>
  <li>c</li>
</ul>