Question

I needed to create a input mask for a jQuery datepicker in my Rails app, where the first form field uses m/d/yy format and the datepicker populates a hidden input with the proper database format.

I was using SimpleForm, and so I extended my own input so that the input is preceded by the mask.

I got everything set up and when checking out the browser, it all just worked well before I thought I would be done.

The form ends up with two inputs for the same attribute, each with the same id and name. I never thought this would work. Checking the development log I only see one date getting submitted, the second of the two which is the one that has the proper format for the database.

Is this all okay? Should I take some extra steps even though this appears to work fine, and more importantly, can someone explain what’s going on under the hood that results in this behavior?

Thanks!!

Answer 1

Rails uses the Hash params to store fields submitted. When you declare two or more inputs using the same name, it happens the same as if you do something like

h=Hash.new
h[:name]="foo"
h[:name]="bar"

Result is bar because the foo was overwritten. So the “winner” is always the field value which the browser last appended to postdata.

But if I where you, I would not rely on the browser that the second field gets appended at last.