从样式表中读取CSS属性 [英] read CSS property from stylesheet
问题描述
我尝试访问像这样的css属性 -
.box {
position:absolute;
背景颜色:红色;
height:10px;
width:10px;
JS:
var height = $('。box')。css('height');
我知道,上面的代码是错误的,而且这实际上不起作用 .box
在DOM中不可用。
另一件我试过的:
<$ pss('height'); p $ p> var height = $(< span class ='box'>< / span>)。
我的问题是:如何获得 .box
没有任何元素在DOM中,类为 box
?
在现代浏览器上,您可以使用 document.stylesheets ,样式表需要在原始的HTML中,并且源代码需要匹配相同原产地政策,即您不能从Chrome扩展插入样式表,因为它不会在document.stylesheets中显示
$ b
CSS
.box {
position:absolute;
背景颜色:红色;
height:10px;
width:10px;
Javascript
function propertyFromStylesheet(selector,attribute){
var value;
[] .some.call(document.styleSheets,function(sheet){
return [] .some.call(sheet.rules,function(rule){
if (selector === rule.selectorText){
return [] .some.call(rule.style,function(style){
if(attribute === style){
value = rule.style.getPropertyValue(attribute);
return true;
}
return false;
});
}
返回false;
});
});
返回值;
console.log(propertyFromStylesheet(。box,height));
输出
10px
在 jsfiddle
I am trying to access css property like this -
.box{
position:absolute;
background-color:red;
height:10px;
width:10px;
}
JS:
var height = $('.box').css('height');
i know, above code is wrong and this actually doesn't work as .box
is not available in DOM.
Another thing that i tried :
var height = $("<span class='box'></span>").css('height');
My question is: how can i get height of .box
without having any element in DOM with class box
?
On a modern browser you could use document.stylesheets, and the stylesheet would need to be in the original HTML and the source needs to match the Same Origin Policy, i.e. you can't inject the stylesheet from say a Chrome extension as it does not show in document.stylesheets
CSS
.box {
position:absolute;
background-color:red;
height:10px;
width:10px;
}
Javascript
function propertyFromStylesheet(selector, attribute) {
var value;
[].some.call(document.styleSheets, function (sheet) {
return [].some.call(sheet.rules, function (rule) {
if (selector === rule.selectorText) {
return [].some.call(rule.style, function (style) {
if (attribute === style) {
value = rule.style.getPropertyValue(attribute);
return true;
}
return false;
});
}
return false;
});
});
return value;
}
console.log(propertyFromStylesheet(".box", "height"));
Output
10px
On jsfiddle
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