Bootstrap 2 (span) Vs Bootstrap 3 (col-md)

Question

I use to work on an asp.net mvc web application using Bootstrap v2.0, where i use the following to divide the screen into 3 parts 4x4x4 :-

<div class="box span4">
...
</div>
<div class="box span4">
...
</div>
<div class="box span4">
...
</div>

while on bootstrap v3.0 seems i need to do the following :-

 <div class="row">
    <div class="box col-md-4"></div>
  <div class="box col-md-4"></div>
  <div class="box col-md-4"></div>
</div>

so i have these 2 questions regarding the above:-

• is using span on bootstrap v2.0 have the same effect as using col-md on bootstrap v3.0 ?

• on bootstrap v3.0 what does col-md-4 exactly do ??.. does it mean that the div will occupy 4 columns on large & Medium sized screens, while it will move down on small and extra small screens ?

Answer 1

Actually the different is in there break point. span breaks the layout at 767px where col-md- breaks the structure at 991px.

col-md-4 means a div will occupy 3 column on large and medium screen, and will adopt 100% bellow 992px.