Javascript & JQuery together

Is there a way to use Javascript & JQuery together like

$('#what').style.background = 'blue';

 

Not like that, use the jQuery css function instead.
$('#what').css('background', 'blue');

 

I understand that. I wanted to to know if there's a way to get the id with JQuery then connect it to javascript

 

The jQuery get function gives you access to the DOM element.
$('#what').get(0).style.background = 'blue';

You need to give it a number to avoid getting an array back, even when there is just one element.