You were waiting for it. He did it! Thanks for 
@heimindanger contribution, now our package is working on client side.
How to get it
https://www.npmjs.com/package/steem
https://github.com/adcpm/steem
How to use it
<script src="./steem.min.js"></script>
<script>
steem.getAccounts(['ned', 'dan'], function(err, response){
console.log(err, response);
});
</script>
Documentation
https://github.com/adcpm/steem/tree/master/doc
If you need more informations, i'm available on the chat with the id 