It’s really easy to get Button ID. Just follow the steps below..
Head over to your website page where the button is located of which you want to get the Button ID. Like I want to find the button ID of the menu button of which I need to add the Popup, so when I click on that button the popup should be appeared.
Right here i want to find the ID of the Support link, to do that i will right click on the Support Link and there will be inspect element option in popup window, Click on that option in the popup menu.
After Clicking on "Inspect Element" there will be a new windows popup at the bottom of the browser, on which you will see highlighted line, that line contains the code of the link. You then needs to find the "id" attribute writting on that line.
If you didn't find the "id" attribute on that specific highlighted line, Go up one line and check if the parent line have the "id" attribute. If yes, the double click on that attribute and only copy part after "=" equal sign.