casper.start(URL, function() { casper.page.injectJs('C:/Users/Mike/Documents/n1k0-casperjs-bc0da16/jquery-1.10.2.min.js'); var names = $('span.author-name'); this.echo(names); this.exit(); } ReferenceError: Can't find variable: $ What do I do? I've tried this too when creating the casper instance: var casper = require('casper').create({ // I've tried both commented lines below // clientScripts: ['