循环遍历jquery中的元素集

Question

$('form td .hint p') this jquery selector returns back a list [p,p,p,p,p,p] .

I would like to know what's the best way to loop through each of those, check their css values, and do something if the css value = something I want.

I have this function to show and hide a tooltip, but I only want one tooltip to be shown at a time. While doing mouseover and mouseout works, it's buggy because currently I'm using parent(), next(), and child(), to find the right element, and jquery instantaneously inserts a div wrapping around the element I'm showing and hiding. So basically I'm trying to force all other p elements that have display:block to hide every time mouseover occurs.

Currently doing this:

target = $('form td .hint p');
target[0].css('display') gives an error.

target.css('display') seems to only return the css of the first one.

Answer 1

Use each() :

var displays = '';
$("p").each(function(i, val) {
  displays += "Paragraph " + i + ": " + $(this).css("display") + "\n";
});
alert(displays);

The reason this fails:

var target = $("p");
var display = target[0].css("display");

is that target[0] is not a jQuery object. You could do this:

var display = $(target[0]).css("display");

Also, if you read the documentation for css() :

Return a style property on the first matched element.

Two other points worth mentioning.

Firstly, I wouldn't advise doing a tooltip yourself. Get one of the many plugins for this. I've used this one previously and it did the job.

Secondly, if you're checking CSS display values, there may be a shortcut worth using. For instance, you could do this:

$("p").each(function() {
  if ($(this).css("display") == "none") {
    $(this).addClass("blah");
  }
});

but you can also use the :hidden and :visible selectors, so:

$("p:hidden").addClass("blah");

Checking values of css() calls is largely unreliable as you're only checking inline styles and not stylesheet values.