Selecting an element by its attribute when it has a colon in its name

问题

Consider the CSS selection I have here:

http://jsfiddle.net/dx8w6b64/

/* This works:
 #myChart .ct-series-b .ct-bar { 
 */


/* This does not (chromium, glnxa64) */
['ct\:series-name'='second'] .ct-bar {
  /* Colour of your points */
  stroke: black;
  /* Size of your points */
  stroke-width: 20px;
  /* Make your points appear as squares */
  stroke-linecap: round;
}

This is a sample chart using https://gionkunz.github.io/chartist-js/

I am trying to select the ct-bar elements:

The colon appears to be throwing off the selector. I have tried various escape approaches :, \3A with a space after, single and double quotes - no luck.

回答1:

I've never used Chartist, but judging by the ct: namespace prefix, it appears to be an extension to SVG markup. So you're no longer really dealing with HTML here; you're dealing with XML, because SVG is an XML-based markup language.

Escaping the colon or otherwise specifying it as part of the attribute name doesn't work because the ct: no longer becomes part of the attribute name when it's treated like a namespace prefix (which is what it is). In a regular HTML document, an attribute name like ct:series-name would indeed include the prefix, because namespace prefixes only have special meaning in XML, not in HTML.

Anyway, the web inspector shows the following XML for your svg start tag:

<svg class="ct-chart-bar" xmlns:ct="http://gionkunz.github.com/chartist-js/ct" width="100%" height="100%" style="width: 100%; height: 100%;">

What you need to do is reflect this XML namespace in your CSS using a @namespace rule:

@namespace ct 'http://gionkunz.github.com/chartist-js/ct';

And, rather than escaping the colon, use a pipe to indicate a namespace prefix:

[ct|series-name='second'] .ct-bar {
  stroke: black;
  stroke-width: 20px;
  stroke-linecap: round;
}

And it should work as expected.

回答2:

You shouldn't quote the attribute name, otherwise you are correctly escaping the colon.

[ct\:series-name='second']

See https://msdn.microsoft.com/en-us/library/ms762307(v=vs.85).aspx

回答3:

It seems like the namespace selector would work only when the namespace is defined within the CSS itself in the below format:

@namespace <namespace-prefix>? [ <string> | <uri> ];

From Selectors Spec: ^{emphasis is mine}

The attribute name in an attribute selector is given as a CSS qualified name: a namespace prefix that has been previously declared may be prepended to the attribute name separated by the namespace separator "vertical bar" (|).

An attribute selector with an attribute name containing a namespace prefix that has not been previously declared is an invalid selector.

Once we add the namespace definition for ct into the CSS, the namespace based selector works as expected. The namespace's URI was taken from the <svg> tag that was generated.

var data = {
  labels: ['W1', 'W2', 'W3', 'W4', 'W5', 'W6', 'W7', 'W8', 'W9', 'W10'],
  series: [{
    name: 'first',
    data: [1, 2, 4, 8, 6, -2, -1, -4, -6, -2]
  }, {
    name: 'second',
    data: [3, 4, 2, 6, 3, 2, 1, 4, 6, 2]
  }]
};

var options = {
  high: 10,
  low: -10,
  onlyInteger: true
};

new Chartist.Bar('.ct-chart', data, options);

@namespace ct url(http://gionkunz.github.com/chartist-js/ct);
[ct|series-name="second"] .ct-bar {
  stroke: black !important; /* without important it doesn't seem to work in snippet but works in fiddle */
  stroke-width: 20px;
  stroke-linecap: round;
}

<script src="https://cdn.jsdelivr.net/chartist.js/latest/chartist.min.js"></script>
<link href="https://cdn.jsdelivr.net/chartist.js/latest/chartist.min.css" rel="stylesheet" />
<div id="myChart" class="ct-chart" style="height:400px"></div>

Fiddle Demo.

Note: The below selector doesn't work even after the namespace definition is added. The reason for this is provided by BoltClock in his answer.

[ct\:series-name="second"] .ct-bar {}

来源：https://stackoverflow.com/questions/34446361/selecting-an-element-by-its-attribute-when-it-has-a-colon-in-its-name

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javascript

css

svg

css-selectors

chartist.js