created a new alert for browser-blocked error

This involved adding a new div to the index page, adding the new div id to the css, and a lot of work in locate.js. showAlert and hideAlert now both take a parameter which is the appropriate alert div's ID. I also moved the setTimeout line to the showAlert function since showAlert is now called in multiple places. 

I'm sure you can come up with better wording for the browser alert.

This pull request says that it can't automatically merge these branches because of your frowny face fix from earlier today (I didn't re-fork). But that fix is included in this pull request.

See what you think, and hope it helps. Let me know if you need any further help with this!