Putting HTML from a outside sources into your blog's post.

How to put HTML or JavaScript  codes into your blog's post. 

Put code inside a post:-

• Copy the code from the third party site

• Go to blogger and Edit the Post (or Page) that you want to put it on

• Switch into HTML mode

• Paste the code in at the place where you want the item to go.
  If you are not familiar with HTML, it may help to put in some marker text  at the place where you want the product link while you're still in Compose mode.  Then switch to Edit HTML mode, find it and replace it with the third-part code.

• Switch back to Compose mode
  This sometimes lets you see the 3rd party item within the post editor - although sometimes it just shows as a blank box, or even just as a blank line (I sometimes surround lines like this with some marker text , eg xxx, while I'm editing the post, to make sure I don't accidentally over-type of the code.
  If you forget to go back to Compose mode before you press Publish, you may get confused the next time you edit a post.

With these simple steps you can add html/javascript widgets to your blog's post.