The aforementioned blog which I am posting was the severe demand of one of my client who was wondering if we could deliver some code that will be executed on every standard screen of Salesforce.
So , the theoretical requirement was cited on the fact that Mr. Client was in urge of some code which would run on every standard page load in salesforce. For this I made an recipe which I am sharing below. Hope that you like it .
For this, You can make one "Narrow Home Page Component".
In that component you can simply use below JS code and alter according to your need.
var doc = window.top.document;
var head = doc.head;
var scriptElement = doc.createElement('script');
scriptElement.async = true;
scriptElement.innerHTML = "alert('test1')";
and add that to your home page layout.
Make sure you have enabled that sidebar component to show on all pages of your sfdc.
Setup -> customize -> user Interface
You can also use this code by a deploying this package -
NOTE: After deployed this package please assign "JS on Every Screen Layout" to System Administraor Profile or profile that you want to use this functionility.