JavaScript ES6, 6563 65 bytes
alert([...[for(c of prompt()].map(e=>e)c.charCodeAt().toString(2))].join(' '))
This is rather long, thanks to JavaScript's long function names. The Stack Snippet below is the rough ES5 equivalent, so it can be run in any browser. Thanks to edc65 for the golfing improvements.
alert(prompt().split('').map(function(e){return e.charCodeAt().toString(2)}).join(' '))