Find an item in a context with jQuery
I have this code in JS to jQuery:
<!DOCTYPE html>
<html>
<head>
<script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.3.2/jquery.min.js"></script>
<title>test</title>
</head>
<body>
<ul id="ul1">
<li id="li11">11</li>
<li id="li12">12</li>
<li id="li13">13</li>
</ul>
<ul id="ul2">
<li id="li21">21</li>
<li id="li22">22</li>
<li id="li23">23</li>
</ul>
<pre id="result"></pre>
</body>
</html>
<script>
$(function(){
var liFind = $("#li21");
var liFindDoc = document.getElementById("li21");
var ul1 = $("#ul1");
var ul2 = $("#ul2");
$("#result").append( "li exist: "+$(liFind开发者_如何学JAVA).length+", "+$(liFind).html()+"<br />");
$("#result").append( "find ul 1 : "+$(ul1).find(liFind).length+"<br />");
$("#result").append( "find ul 2 : "+$(ul2).find(liFind).length+"<br />");
$("#result").append( "children ul 1 : "+$(ul1).children(liFind).length+"<br />");
$("#result").append( "children ul 2 : "+$(ul2).children(liFind).length+"<br />");
$("#result").append( "filter ul 1 : "+$(ul1).filter(liFind).length+"<br />");
$("#result").append( "filter ul 2 : "+$(ul2).filter(liFind).length+"<br />");
$("li").each(function(i,val){
$("#result").append("li "+$(val).attr("id")+": "+(liFind==val)+" - "+(liFindDoc==val)+"<br />");
});
$(ul1).children().each(function(i,val){
$("#result").append("children II ul 1 : "+(liFind==val)+" - "+(liFindDoc==val)+"<br />");
});
$(ul2).children().each(function(i,val){
$("#result").append("children II ul 2 : "+(liFind==val)+" - "+(liFindDoc==val)+"<br />");
});
$(ul1).find("li").each(function(i,val){
$("#result").append("find II ul 1 : "+(liFind==val)+" - "+(liFindDoc==val)+"<br />");
});
$(ul2).find("li").each(function(i,val){
$("#result").append("find II ul 2 : "+(liFind==val)+" - "+(liFindDoc==val)+"<br />");
});
$("#result").append("'SOLUTION' ::: closest li->ul: "+ $(liFind).closest('ul').attr("id") +"<br />");
});
</script>
and get this result:
- 11
- 12
- 13
- 21
- 22
- 23
li exist: 1, 21
find ul 1 : 0 find ul 2 : 0 children ul 1 : 3 children ul 2 : 3 filter ul 1 : 0 filter ul 2 : 0 li li11: false - false li li12: false - false li li13: false - false li li21: false - true li li22: false - false li li23: false - false children II ul 1 : false - false children II ul 1 : false - false children II ul 1 : false - false children II ul 2 : false - true children II ul 2 : false - false children II ul 2 : false - false find II ul 1 : false - false find II ul 1 : false - false find II ul 1 : false - false find II ul 2 : false - true find II ul 2 : false - false find II ul 2 : false - false 'SOLUTION' ::: closest li->ul: ul2Question How can I tell if an element is in a context, for example in the case above, as whether a "li" is in a "ul"? with jQuery using a method such as "find".
The second parameter of your selector is reserved for a context:
$("ul", "body").length; // how many UL's are within the body?
Of course that's more complicated than just making a more detailed selector:
$("body ul").length; // how many UL's are within the body?
Additionally, you can always query the parents:
$("ul").parents("body").length; // is a BODY up there?
Using "find" can be like this:
$("ul").find("li").length; // how many LI's (included grandchildren) within UL?
I would use closest() to find parent context, unless you can do it in the selector.
$('#li22').closest('ul').length;
or as a plugin:
$.fn.context = function(context) {
return !!$(this).closest(context).length;
};
console.log( $('#li22').context('kbd') ); // prints false
加载中,请稍侯......
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