If you want to change the base object that quick.js interacts via, you can change it with:
var quickjs = _ // sets base object to quickjs
quickjs.edit()
var lib = _
lib.addClass()
Changing a text color:
<p id="changeToRed">I will be changed to red!</p>
<script>
// one way to do it
_.setCSS("#changetoRed", "color", "red")
// another way, if you already
// have your element stored in a variable
var changeClr = _.get("#changeToRed")
_.setCSS(changeClr, "color", "red")
</script>