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Assorted jQuery questions

1.) What's the difference between these two queries, exactly?

$( "#orderedlist li" )
$( "#orderedlist>li" )

2.) In the jQuery file itself there is a function that returns the following:

function now(){
    return +new Date;
}

What does that mean? I've never seen +new before.

3.) In a brief skimming of a tutorial, I observed the following samples:

// use this to reset a single form
$( "#reset" ).click( function()
{
    $( "form" )[0].reset();
});

// use this to reset several forms at once
$( "#reset" ).click( function()
{
    $( "form" ).each( function()
    {
        this.reset();
    });
});

When I try to reference my own queries by array indexes, they don't seem to work. Yet this example clearly did when I tested it. What could I be doing wrong?

Edit: I'll put this one into its own question soon. Edit 2: Actually I may be able to debug it myself. Hang on...

I have guesses to each of these, but short of dissecting the jQuery file itself in full, I'm not completely certain what's at work here. Help appreciated.

like image 702
Daddy Warbox Avatar asked Jul 05 '09 11:07

Daddy Warbox


1 Answers

Question #1:

  • #orderedlist li is a "descendant selector": an li anywhere within an #orderedlist.
  • #orderedlist>li is a "child selector": an li which is a direct child of an #orderedlist.

Question #2:

That's using the unary plus operator - it's equivalent to:

return Number(new Date);

see: http://xkr.us/articles/javascript/unary-add/ - it gives the number of milliseconds since the UNIX epoch.

Question #3:

I don't know about this one. Could you post a minimal failing example?

like image 87
RichieHindle Avatar answered Sep 28 '22 06:09

RichieHindle