Question

I have a form_tag that submits a user’s search remotely to a Rails controller method, which returns the results in JS format.

How can I automatically submit this form:

1. When a user has entered in at least 2 characters
2. When the user has paused for at least 1 second?

Answer 1

Bind a keypress handler to the input using jQuery. In the callback, start a timer using setTimeout to submit the form after one second and keep a hold of the timer ID that setTimeout returns to you. If you have a non-null timer ID when your keypress callback is triggered, stop the timer with clearTimeout and set the timer ID to null; if they also have two characters at this point, then start the timer (again) and store the timer ID (again).

So, you have a process in the keypress handler like this:

1. Do I have a timer running?
   • If yes, clearTimeout, null the timer ID, and continue.
   • If no, then continue on.
2. Do I have at least two characters?
   • If yes, start the timer with setTimeout and store the timer ID, the function attached to the timer would submit the form.
   • If no, then continue on.
3. …
4. Profit.