Can a DOM element have an ID that contains a space?

Question

And if so, how do you select on with jQuery? I.e., $("#a b") looks for all <b> nodes within the node with id=a.

Answer 1

According to the HTML 4.0 specification for basic types:

ID and NAME tokens must begin with a letter ([A-Za-z]) and may be followed by any number of letters, digits ([0-9]), hyphens ("-"), underscores ("_"), colons (":"), and periods (".").

And even if spaces were valid, an id attribute with spaces would be interpreted by jQuery as an ancestor descendant selector with the current selector syntax.

Answer 2

Short answer is no. Letters, numbers, underscores, hyphens, periods and colons only.

(darn, karim beat me to it.)

Answer 3

This is an argument by analogy.

Consider the CLASS selector. Not the same as ID, but there are simlarities.

You obviously can't have a class name with an embedded space because a list of classes

<p class='a b c'>some text</p>

could not be distinguished from a single name with spaces.

Ok, you can't have a list of id names, anyway, so the analogy falls apart, but I think we've become too quick to try to insert spaces where they don't belong.