Selection API

Syntax#

Selection sel = window.getSelection();
Selection sel = document.getSelection(); // equivalent to the above
Range range = document.createRange();
range.setStart(startNode, startOffset);
range.setEnd(endNode, endOffset);

Parameters#

Parameter	Details
startOffset	If the node is a Text node, it is the number of characters from the beginning of `startNode` to where the range begins. Otherwise, it is the number of child nodes between the beginning of `startNode` to where the range begins.
endOffset	If the node is a Text node, it is the number of characters from the beginning of `startNode` to where the range ends. Otherwise, it is the number of child nodes between the beginning of `startNode` to where the range ends.
## Remarks#
The Selection API allows you to view and change the elements and text that are selected (highlighted) in the document.

It is implemented as a singleton Selection instance that applies to the document, and holds a collection of Range objects, each representing one contiguous selected area.

Practically speaking, no browser except Mozilla Firefox supports multiple ranges in selections, and this is not encouraged by the spec either. Additionally, most users are not familiar with the concept of multiple ranges. As such, a developer can usually only concern themselves with one range.

Deselect everything that is selected

let sel = document.getSelection();
sel.removeAllRanges();

Select the contents of an element

let sel = document.getSelection();

let myNode = document.getElementById('element-to-select');

let range = document.createRange();
range.selectNodeContents(myNode);

sel.addRange(range);

It may be necessary to first remove all the ranges of the previous selection, as most browsers don’t support multiple ranges.

Get the text of the selection

let sel = document.getSelection();
let text = sel.toString();
console.log(text); // logs what the user selected

Alternatively, since the toString member function is called automatically by some functions when converting the object to a string, you don’t always have to call it yourself.

console.log(document.getSelection());