css response displays differently - css

Question

one issue I don't quite understand.
I made an online sample, when I'm resizing the window, the SPANs response one by one.
Online sample http://jsfiddle.net/Pva7y/1/
Online Images
However, I copied the same code to my local html, the SPANs response just together.
Local Image.
why different? Thanks
HTML:
<div class="row ">
<div class="span7 blue">
1
</div>
<div class="span2 red">
2
</div>
<div class="span3 green">
3
</div>
</div>
CSS:
.blue{background-color:blue;}
.red{background-color:red;}
.green{background-color:green;}

Answer 1

First thing is that you forgot to use container div. Correct pattern is
<div class="container">
<div class="row">
<div class="span12">
1 2 3
</div>
</div>
</div>
See corrected jsfiddle (1).
Next, if you want your page to be responsive and fit the layout to the size of the viewport you have to also include bootstrap-responsive.css. See jsfiddle (2). In your local HTML you used either both bootstrap.css and bootstrap-responsive.css or prior files merged to one CSS for reducing client-server requests number.

Answer 2

Your <div>s are floated in your Fiddle, but they are not floated in your local html judging from your screenshot. And since bootstrap.css floats the <div> element with a class of span, I am guessing that bootstrap.css is not loaded properly in your local html file.
A way to troubleshoot your issue is to check the Inspector (if you're using Chrome), or Firebug (if you're using Firefox). Look at the computer style of the three <div>s in your fiddle AND your local html, and compare them. They must have been styled differently because they look different on the same browser, so that's the way to start troubleshooting.