Question

Is there a function in vanilla JS (i.e. not JQuery etc) to determine the activeElement‘s child number?

I’m currently using this code, but I’d prefer to use selCell = document.activeElement.childNumber; (for example) rather than looping through the parent:

for(var j = 0; cell = document.activeElement.parentNode.cells[j]; j++)
    if(cell == document.activeElement)
        selCell = j;

If any clarification is needed (such as HTML context), ask away!

Thanks a lot!

Answer 1

Table cells keep their own index…

selCell = document.activeElement.cellIndex;

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For other element types, a common solution is to start at the current element, and iterate through previous siblings, incrementing a counter every time an element is encountered.

var i = 0;

while(elem = elem.previousSibling)
    if (elem.nodeType === 1)
        i++;