Re: Element.createElement proposal

In article <[email protected]>,
 Robert O'Callahan <[email protected]> wrote:

> On 11/8/09 1:20 PM, Johnny Stenback wrote:
> > On 08/10/2009 06:06 PM, Zack Weinberg wrote:
> >> What's wrong with
> >>
> >> var parent = document.getElementById("putsvghere"); // HTML elt
> >> var svg = parent.addChild('svg'); // HTML5 'svg' elt = SVG root elt
> >> var circle = svg.addChild('circle', {...}); // SVG 'circle'
> >
> > What should that code do if you replace parent.addChild('svg') with
> > parent.addChild('a')?
> 
> For simplicity I would say that e.addChild should always inherit the 
> namespace of e.
> 
> > And does this always append, or insert at the
> > beginning, what if I want to insert somewhere in the middle etc etc?
> 
> I think it should always append. The use cases for the other positions 
> are much fewer and can be handled with existing DOM APIs.

In article <[email protected]>,
 Robert O'Callahan <[email protected]> wrote:

> What about HTML5 SVG parsing? We want a solution that works well in an 
> HTML document.
> 
> So why not use the HTML5 parsing rules to determine which namespace the 
> element gets? The HTML5 parser already has a list of which elements 
> should be SVG or MathML.

The HTML5 parsing rules depend on context. Also, rules like deciding 
what to do with <font> only make sense in parsing.

However, I like the idea of addChild() and I like the idea of being able 
to pass attributes as a JS object of key-value pairs.

I suggest the following (inspired by the HTML5 parsing algorithm but 
simplified and XBL2 attribute support added):

 * Element.addChild(name, attrs=null): Creates an element in the same 
namespace as |this| with the local name /name/. If attrs is not null, 
adds attributes to the newly-created element as described below. Appends 
the newly-created element as the last child of |this|.

  - Exception: if |this| is in the http://www.w3.org/1999/xhtml 
namespace or one of the elements that make the HTML5 parsing algorithm 
allow HTML content: Behave like Document.createElement() below for the 
element creation part.

 * Document.createElement(name, attrs=null): If /name/ is "svg", creates 
an element in the http://www.w3.org/2000/svg namespace with the local 
name "svg". If the /name/ is "math", creates an element in the 
http://www.w3.org/1998/Math/MathML namespace with the local name "math" 
Otherwise, creates an element in the http://www.w3.org/1999/xhtml 
namespace with the local name /name/. If attrs is not null, adds 
attributes to the newly-created element as described below.

 * Adding attributes extracts the key-value pairs from the JS object and 
for each pair runs the following steps:
   - If /key/ starts with "xml:", call 
setAttributeNS("http://www.w3.org/XML/1998/namespace", key, value) on 
the newly-created element.
   - If /key/ starts with "xmlns:", call 
setAttributeNS("http://www.w3.org/2000/xmlns/", key, value) on the 
newly-created element.
   - If /key/ starts with "xlink:", call 
setAttributeNS("http://www.w3.org/1999/xlink", key, value) on the 
newly-created element.
   - If /key/ starts with "xbl:", call 
setAttributeNS("http://www.w3.org/ns/xbl", key, value) on the 
newly-created element.
   - Otherwise, call setAttributeNS(null, key, value).

-- 
Henri Sivonen
[email protected]
http://hsivonen.iki.fi/