content_tag
content_tag(name, content_or_options_with_block = nil, options = nil, &block)Returns an HTML block tag of type name surrounding the content. Add <a href="/rails/HTML">HTML</a> attributes by passing an attributes hash to options. For attributes with no value like (disabled and readonly), give it a value of true in the options hash. You can use symbols or strings for the attribute names.
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>
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.
<% content_tag :div, :class => "strong" do -%> Hello world! <% end -%> # => <div class="strong"><p>Hello world!</p></div>
8Notes
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=>'') # => "
Empty elements
If you want to output an empty element (self-closed) like "br", "img" or "input", use the +tag+ method instead.
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 #=>
If you used #each you would get this (which is probably a mistake): #=>
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?))
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
}
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.
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.
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
