flot/flot — pull request #1084 by execjosh (2013-06-29 14:40:28+00:00)
Title: Also stop at root when extracting CSS color

This change adds an additional check for whether the parent element is `null` or `undefined` in `$.color.extract`. This can happen when working with elements that have not yet been added to the DOM under `

`.

Consider the following example pie chart.

```js
var elm = $("

")
.css({
width: "240px"
, height: "320px"
})
var data = [
{label: "One", data: "33"}
, {label: "Two", data: "33"}
, {label: "Three", data: "33"}
]
var opts = {
legend: {
show: true
}
, series: {
pie: {
show: true
}
}
}
$.plot(elm, data, opts)
elm.appendTo($("body"))
```

When flot inserts each legend row, it tries to use the same color as the corresponding graph part, unless it was explicitly specified in the options. However, in this example, `$.color.extract` runs into an unexpected `null` reference because `

` is not an ancestor of `elm`. Specifically, a `TypeError: Cannot read property 'nodeName' of undefined` would be thrown.