When using vim some django templates, for example:

 {% if sth %} 
something
 {% endif %} 

The indentation I require is as above, but in vim it will be forced to automatically indent the line "

" forward and become:

 {% if sth %} 
something
 {% endif %} 

You must finish typing the line "

" and manually change the indentation. .

What I understand is that because this is an html file, vim treats it as a normal html indentation format and ignores the if tag in django.
So what should we do to make vim treat "{% %}" as a tag in HTML?