524288?
2147483647?
-1?
No, that’s not my bank account balance…

Unlike any other attribute, maxlength is implicitly present on any input-element. I had to find this out the hard way trying to select only input-elements with an explicitly set maxlength via the jQuery-selector input[maxlength].

Well, that didn’t work. input[maxlength] returns all inputs, regardless of whether they have maxlength or not. The only conclusion this leaves us with is that browsers add a certain maxlength-value implicitly to any input-field.

What’s my browser doing with maxlength?

That’s exactly what I asked myself. A quick browser test left me quite surprised, but, hey – what did I expect – every browser behaving the same? Not in this world…

Every browser rendering engine implies a different value. The most reasonable browsers are Firefox (surprised?) and Opera – they are at least assuming a negative value. The other values seem (at least to me, maybe I’m just missing some nerdy inside joke) completely arbitrary are natural limits: 2147483647 is the highest possible 32-bit-number (2^32 /2 or 0111 1111 1111 1111 1111 1111 1111 1111), while 524288 is the same in 16 bit:

jQuery to the rescue

So back to the original problem – my solution for selecting only input-fields with maxlength-attributes based on these findings is as follows:

var inputs = $('input[maxlength!=-1][maxlength!=524288][maxlength!=2147483647]');

Ugly, I know. But it works.

Take the Browser Test
and post your result in the comment section!

Why?

Why would I want to select only this subset of input elements anyway? In my case, it was to display the number of total and remaining characters a user could enter.