Proper way to inject the JavaScript to the SPO page

Hi ganeshsanap,

I use the classic experience.

Unfortunately even though I've tried to run the script after page loaded, the issue still persist.

It looks like something is buffered in the browser and I have to make couple flips to make it work.

Have a look:

• HTML file

<h1><p id="container2"></p></h1>
<script type="text/javascript" src="https://...../JavaScript/InjectTest.js"></script>​

• JS file

function runAfterEverythingElse() {
    document.getElementById("container2").innerHTML = 'Test2';
}
_spBodyOnLoadFunctionNames.push("runAfterEverythingElse");​

• On the page I have Test2 text as expected
  
• Now I change the text in the JS file, unfortunately it has no effect on the page after save

function runAfterEverythingElse() {
    document.getElementById("container2").innerHTML = 'TEST AFTER CHANGES';
}​

• Now I can open the JS file in the browser and I can see there are values before the change, but when I refresh the page, new values appear
  
  

• Now I can refresh the page (Ctrl+F5) and new values will be on place