How to Add Facebook Like to Blogger (very easy)

Step
1. Go to the "Facebook Developers" page: https://developers.facebook.com/docs/plugins/like-button/

2. Set the options you want. Specifically, select whether you want a "Like" or a "Recommend" button. The sample button on the page will automatically update to reflect your selections. 

•  URL to Like: link to your page such as: https://www.facebook.com/donghodeptanphat
• Width: my sidebar is 150px so i set 148px, like this.
• Layout: you can test by yourself
• Action type: Like or Recommend

3. Click "Get Code". You will see something that looks like this:

4. Choose "IFRAME" tag, and copy the source code:

<iframe src="//www.facebook.com/plugins/like.php?href=https%3A%2F%2Fdevelopers.facebook.com%2Fdocs%2Fplugins%2F&amp;width&amp;layout=standard&amp;action=like&amp;show_faces=true&amp;share=true&amp;height=80&amp;appId=609868749050667" scrolling="no" frameborder="0" style="border:none; overflow:hidden; height:80px;" allowTransparency="true"></iframe>

5. Go to your Blogger Dashboard, and choose "Layout", Click "Add Gadget"

6. Choose HTML/JAVASCRIPTS.

7. write title, paste the code and click OK

8. Click "Save arrangement"

Have fun!