welsonjs/node_modules/modernizr/feature-detects/css/nthchild.js

35 lines
1.4 KiB
JavaScript

/*!
{
"name": "CSS :nth-child pseudo-selector",
"caniuse": "css-sel3",
"property": "nthchild",
"tags": ["css"],
"notes": [{
"name": "Related Github Issue",
"href": "https://github.com/Modernizr/Modernizr/pull/685"
}, {
"name": "Sitepoint :nth-child documentation",
"href": "https://www.sitepoint.com/atoz-css-screencast-nth-child/"
}],
"authors": ["@emilchristensen"],
"warnings": ["Known false negative in Safari 3.1 and Safari 3.2.2"]
}
!*/
/* DOC
Detects support for the ':nth-child()' CSS pseudo-selector.
*/
define(['Modernizr', 'testStyles'], function(Modernizr, testStyles) {
// 4 `<div>` elements with `1px` width are created. Then every other element has its `width` set to `2px`.
// Then we check if the width of the even elements is different then the width of the odd elements
// while the two even elements have the same width (and the two odd elements too).
// Earlier versions of the tests tried to check for the actual width which didnt work on chrome when the
// browser was zoomed in our out in specific ways.
testStyles('#modernizr div {width:1px} #modernizr div:nth-child(2n) {width:2px;}', function(elem) {
var elems = elem.getElementsByTagName('div');
var correctWidths = elems[0].offsetWidth === elems[2].offsetWidth &&
elems[1].offsetWidth === elems[3].offsetWidth &&
elems[0].offsetWidth !== elems[1].offsetWidth;
Modernizr.addTest('nthchild', correctWidths);
}, 4);
});