jQuery index() in vanilla javascript

javascript, jquery

Solution

You can build your own function :

function indexInParent(node) {
    var children = node.parentNode.childNodes;
    var num = 0;
    for (var i=0; i<children.length; i++) {
         if (children[i]==node) return num;
         if (children[i].nodeType==1) num++;
    }
    return -1;
}

Demonstration (open the console)

Problem

As per the jQuery api, the complementary operation to .get(), which accepts an index and returns a DOM node, `.index()` can take a DOM node and returns an index. Suppose we have a simple unordered list on the page: ``` <ul> <li id="foo">foo</li> <li id="bar">bar</li> <li id="baz">baz</li> </ul> ``` `.index()` will return the position of the first element within the set of matched elements in relation to its siblings: ``` alert('Index: ' + $('#bar').index(); ``` We get back the zero-based position of the list item: ``` Index: 1 ``` I just want to know, how can we do the same using JavaScript??

Original source

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