jQuery - How to check if an element is an array or single

Question

jQuery 1.7.1

Sometimes I have an element as an array,

<tr><td><input type="hidden" class="p" name="it" value="1"/></td></tr>
<tr><td><input type="hidden" class="p" name="it" value="2"/></td></tr>

The below jQuery code works,

$(".p").each(function(i){
alert($('.p')[i].value);
});

Sometime I have that element as a single element

<tr><td><input type="hidden" class="p" name="it" value="1"/></td></tr>

I want to make sure if the hidden input is an array or a single element before trying to execute the above jQuery code. How can I do that using jQuery?

May I point you towards: "[How do you check if a variable is an array in JavaScript?](http://stackoverflow.com/questions/767486/how-do-you-check-if-a-variable-is-an-array-in-javascript)" — David Thomas, Mar 21 '12 at 02:53
@DavidThomas I had a look at that before, but I was looking for a jQuery way of doing it. Thanks — SyAu, Mar 21 '12 at 03:13

score 7 · Accepted Answer · answered Mar 21 '12 at 02:54

7

Actually, that code works fine for both one input and two inputs.

But, use the size method to check:

if ($(".p").size() > 1) {
    $(".p").each(function(i){
        alert($(this).value);
    });
}

answered Mar 21 '12 at 02:54

benesch

5,239
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Thanks for pointing me that the code is correct. I double checked my original code and noticed I had $('.a')[i] instead of $('.a')[i].value. For information, I have many input type hidden array elements like $('.p'), $('.a') etc. and for easier understanding I simplified my question. – SyAu Mar 26 '12 at 00:38

Jon Gauthier · Answer 2 · 2012-03-21T02:59:19.493

4

You could check the length of the set jQuery returns.

var p = $('.p');
if ( p.length == 1 )
    // single
else if ( p.length > 1 )
    // set

But this, I believe, is not your problem. Your jQuery code should not reload $('.p') on each iteration. Try this — it'll work with one or multiple matched elements:

$(".p").each(function(){
    alert(this.value);
});

edited Mar 21 '12 at 02:59

answered Mar 21 '12 at 02:52

Jon Gauthier

25,202
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Thanks @Hans Engel. Your answer solved my problem. In fact, all other replies are also useful. – SyAu Mar 21 '12 at 03:10

score 1 · Answer 3 · answered Mar 21 '12 at 02:57

1

The result of a DOM query is always a jQuery object. It cannot be a single element. $(".p").length will tell you the number of elements in the returned object, which can be 0 if the query matched no objects.

answered Mar 21 '12 at 02:57

Dmitry Leskov

3,233
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jQuery - How to check if an element is an array or single

3 Answers3