get the nth-child number of an element in jquery

Question

I have a class of multiple \'DIV\' elements and inside it are list of \'p\' elements. See below:

    
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Answer 1

Use the parameter-less version of the .index() method to find the position of the element relative to its siblings:

$('.container').children('p').hover(function() {
     var index = $(this).index() + 1;
});

Note that the result of .index() will be zero-based, not one-based, hence the + 1

Answer 2

$('.container').children('p').hover(function(){
    //get the nth child of p from parent class 'container'
    var n = 1;
    var child = $(this).parent().find("p:eq("+n+")");
});

Should work!

Or if you want to know the index of the hovered element:

$('.container').children('p').each(function(index,element) {
    // use closure to retain index
    $(element).hover(function(index){
        return function() { alert(index); }
    }(index);
}

See http://api.jquery.com/each/

Answer 3

You can use jQuery's index function for that. It tells you where the given element is relative to its siblings:

var index = $(this).index();

Live example | source

The indexes are 0-based, so if you're looking for a 1-based index (e.g., where the first one is 1 rather than 0), just add one to it:

var index = $(this).index() + 1;

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If you're not using jQuery and came across this question and answer (the OP was using jQuery), this is also quite simple to do without it. nth-child only considers elements, so:

function findChildIndex(node) {
    var index = 1;                         // nth-child starts with 1 = first child
    // (You could argue that you should throw an exception here if the
    // `node` passed in is not an element [e.g., is a text node etc.]
    // or null.)
    while (node.previousSibling) {
        node = node.previousSibling;
        if (node && node.nodeType === 1) { // 1 = element
            ++index;
        }
    }
    return index;
}