jQuery - get a list of values of an attribute from

问题:

I have a class .object which has an attribute called level. I want to get a list of all the different values of level on the page so I can select the highest one.

If I do something like:

$(".object").attr("level")

... will that get me a list of values that are the values of the level attribute? I suspect not, but then how do you do something like that?

Note: I don't want to select an HTML object for manipulation as is more common, rather I want to select values of the attribute.

EDIT: In order to get the highest "level" I have done this, but it doesn't seem to work. I will try the other suggested method now.

var highLevel=0;
$.each(".object[level]", function(i, value) {
   if (value>highLevel) {
       highLevel=value;
   }
});

alert(highLevel);

回答1:

$(".object").attr("level") will just return the attribute of first the first .object element.

This will get you an array of all levels:

var list = $(".object").map(function(){return $(this).attr("level");}).get();

回答2:

First part of the question, getting the attribute values into an array. See this question

jQuery get img source attributes from list and push into array

You would say

var levelArray = $('.object').map( function() {
    return $(this).attr('level');
}).get();

Second part of the question , you can use this technique to get the highest value

var maxValue = Math.max.apply( Math, levelArray );

回答3:

<script type="text/javascript"> 
var max = 0;
jQuery(document).ready(function(){ 
    jQuery('.object[level]').each(function(){
        var num = parseInt($(this).attr('level'), 10);
        if (num > max) { max = num; }
    });
    alert(max);
});
</script>

I'm assuming markup like this:

<div class="object" level="1">placeholder</div>
<div class="object" level="10">placeholder</div>
<div class="object" level="20">placeholder</div>
<div class="object" level="1000">placeholder</div>
<div class="object" level="40">placeholder</div>
<div class="object" level="3">placeholder</div>
<div class="object" level="5">placeholder</div>

For my code I get "1000" alerted to me.

Here's another solution, combining several of the other replies from harpo, lomaxx, and Kobi:

jQuery(document).ready(function(){ 
    var list = $(".object[level]").map(function(){
        return parseInt($(this).attr("level"), 10);
    }).get();
    var max = Math.max.apply( Math, list ); 
    alert(max);
});

回答4:

the selector

$(".object[level]")

will give you all the dom elements with class object and an attribute level.

Then you can just use the .each() method to iterate over the elements to get the highest value

回答5:

You can extend the functionality of Jquery and add your own 'attrs' implementation.

Add the following lines of code to your JavaScript file:

jQuery.fn.extend({
    attrs: function (attributeName) {
        var results = [];
        $.each(this, function (i, item) {
            results.push(item.getAttribute(attributeName));
        });
        return results;
    }
});

Now you can get the list of level values by calling:

$(".object").attrs("level")