CSOM: SP is not defined

Here is my error:

Uncaught ReferenceError: SP is not defined

$_global_portal (anonymous function)

SP is not defined and the source is

portal.js?rev=nIRSxJH7DAoMFUDBHc9jFg%3D%3D:1 portal.js?rev=nIRSxJH7DAoMFUDBHc9jFg%3D%3D:1

I know its SharePoint JS file. I tried to load some other JS files suggested in given link but nothing help me to solve this issue.

Please suggest me something on this.