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Indicates whether a flow’s content exceeds available space within a region chain, or if no available chain in which to flow content exists.

Property of apis/css-regions/NamedFlowapis/css-regions/NamedFlow


Note: This property is read-only.

var exceedsRegions = flow.overset;

Return Value

Returns an object of type BooleanBoolean

Indicates whether a flow’s content exceeds available space within a region chain. Also indicates when no chain is available in which to flow content.


// adds a region element to a prescribed container
// if there aren't already enough to display all content
function appendRegion(flowName) {
    var flow = document.getNamedFlows().namedItem(flowName);
    var layout = document.querySelector('#layout_wrapper');
    var region;

    // need to add more regions?
    if (! flow.overset) return(false);

    // assumes CSS such as:
    //   #layout_wrapper > div { flow-from: mainFlow}
    region = document.createElement('div');

    return(true); // perhaps for use in while loop



Not to be confused with regionOverset, which indicates the overset state of individual regions. Only the final region in a chain can be overset.

Related specifications

CSS Regions Module Level 1
W3C Working Draft

See also

Related articles


External resources