Question

I’m getting w3c validation errors with this Javascript code and wonder if a kind gent/lady would spare me a moment to take a gander.

// hide all element nodes within some parent element
function hideAll(parent) {
    var children = parent.childNodes, child;
    // loop all the parent's children
    for (var idx=0, len = children.length; idx<len; ++idx) { /* ERROR HERE */
        child = children.item(idx);
        // if element node (not comment- or textnode)
        if (child.nodeType===1) {
            // hide it
            child.style.display = 'none';
        }
    }
}

The Errors are:

• element “len” undefined
• character “;” not allowed in attribute specification list

The semi-colon at idx<len; is where it goes wrong.

Can someone explain where I’m going wrong with the above code snippet?

Many thanks.

Answer 1

Change it to:

// hide all element nodes within some parent element
function hideAll(parent) {
    var children = parent.childNodes, child;
    // loop all the parent's children
    var len = children.length;
    for (var idx=0; idx<len; ++idx) { /* ERROR HERE */
        child = children.item(idx);
        // if element node (not comment- or textnode)
        if (child.nodeType===1) {
            // hide it
            child.style.display = 'none';
        }
    }
}