Bootstrap is most popular front-end framework right now, it is user friendly responsive option for rapid development.
Bootstrap provides 5 easy steps to modify buttons
Firstly, style the button using these button classes like, .btn-default, .btn-primary, .btn-success, .btn-info, .btn-warning, .btn-danger, .btn-link.
nolvadex online 
Second, sizing the button Large or small buttons add .btn-lg, .btn-sm, or .btn-xs Class
Third, Active state, If you want a button to be active as pressed, Add .active class
Fourth, Disabled state, if you want a button to be disabled. Add .disabled class
Fifth, Button Tags, can add btn classes on an <a>, <button>, or <input> element.
<a class=”btn btn-default” href=”#” role=”button”>Link</a>
<button class=”btn btn-default” type=”submit”>Button</button>
<input class=”btn btn-default” type=”button” value=”Input”>
<input class=”btn btn-default” type=”submit” value=”Submit”>
These are the five easy steps to edit the button using Bootstrap.