var link = document.createElement( "link" );
link.href = '../profolio-theme-' + this.selected_theme+ '.css';
link.type = "text/css";
link.rel = "stylesheet";
link.className = "stylesheet-theme";
link.media = "screen,print";
document.getElementsByTagName( "head" )[0].appendChild( link );
If you want to add a classname:
element.classList.add("bar");
$(".stylesheet-theme").remove();
or
$("script[src='your.js']").remove();