Ensure an element is visible: ``` function ElementAbsolutePosition(elt) [(function(o) o.offsetLeft + (o.offsetParent ? arguments.callee(o.offsetParent) : 0))(elt), (function(o) o.offsetTop + (o.offsetParent ? arguments.callee(o.offsetParent) : 0))(elt)];

    function SetInView(elt, offset) {

        var pos = ElementAbsolutePosition(elt)[1];
        var body = elt.ownerDocument.body;
        if ( pos < body.scrollTop || pos + elt.offsetHeight > body.scrollTop + body.clientHeight ) {

            elt.scrollIntoView();
            body.scrollTop += offset || 0;
        }
    }

```

``` function StringReplacer(conversionObject) function(s) s.replace(new RegExp([k.replace(/(\/|.|*|+|\?|\||(|)|[|]|{|}|\)/g, "\$1") for (k in conversionObject)].join('|'), 'g'), function(str) conversionObject[str]);

    var EscapeEntities = StringReplacer({'&':'&amp;', '<':'&lt;', '>':'&gt;'});

```

Wrapper to XPath for XHTML or XUL documents: ``` function XPath(ref, xpath) {

        doc = ref.ownerDocument || ref;
        var result = doc.evaluate(xpath, ref, null, XPathResult.ANY_TYPE, null);
        switch (result.resultType) {

            case XPathResult.NUMBER_TYPE:
                return result.numberValue;
            case XPathResult.BOOLEAN_TYPE:
                return result.booleanValue;
            case XPathResult.STRING_TYPE:
                return result.stringValue;
        } // else XPathResult.UNORDERED_NODE_ITERATOR_TYPE
        var list = [];
        for ( var node = result.iterateNext(); node; node = result.iterateNext() )
            switch ( node.nodeType ) {
            case node.ATTRIBUTE_NODE:
                list.push( node.value );
                break;
            case node.TEXT_NODE:
                list.push( node.data );
                break;
            default:
                list.push( node );
            }
        return list;
    }

```

``` function TextToHTMLNode(doc, text) {

        var elt = doc.createElement('div');
        elt.innerHTML = text;
        return elt.firstChild;
    }

    function InsertNode(node, pos) pos.parentNode.insertBefore(node, pos);

    function InsertNodeAtBeginning(node, parent) parent.firstChild ? parent.insertBefore(node, parent.firstChild) : parent.appendChild(node);

```

HTML class handling: ``` function HasClass(elt, class) (' '+elt.className+' ').indexOf(' '+class+' ') != -1;

    function SetClass(polarity, elt, class) {

        class = ' '+class+' ';
        var str = ' '+elt.className+' ';
        var pos = str.lastIndexOf(class);
        if (polarity != (pos != -1))
            elt.className = polarity ? str+class : str.substr(0, pos+1)+str.substr(pos+class.length);
    }

```

XUL inline CSS stylesheet: <?xml-stylesheet href="data:text/css, ... " type="text/css"?>