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CSSGroupingRule: insertRule() method - Web APIs | MDN
CSSGroupingRule: insertRule() method Baseline Widely available
The insertRule()
method of the
CSSGroupingRule
interface adds a new CSS rule to a list of CSS rules.
insertRule(rule)
insertRule(rule, index)
rule
A string
index
Optional
An optional index at which to insert the rule; defaults to 0.
The index of the new rule.
IndexSizeError
DOMException
Thrown if index is greater than the number of child CSS rules.
HierarchyRequestError
DOMException
Thrown if rule
cannot be inserted at the specified index due to some CSS constraint.
HierarchyRequestError
DOMException
Thrown if the rule
is a valid statement but not a nested statement .
let myRules = document.styleSheets[0].cssRules;
myRules[0].insertRule(
"html {background-color: blue;}",
0,
); /* inserts a rule for the HTML element at position 0 */