avsej avsej - 7 months ago 46
Javascript Question

How to move cursor to end of contenteditable entity

I need to move caret to end of

contenteditable
node like on Gmail notes widget.

I read threads on StackOverflow, but those solutions are based on using inputs and they doesn't work with
contenteditable
elements.

Answer

There is also another problem.

The Nico Burns's solution works if the contenteditable div doesn't contain other multilined elements.

For instance, if a div contains other divs, and these other divs contain other stuff inside, could occur some problems.

In order to solve them, I've arranged the following solution, that is an improvement of the Nico's one:

//Namespace management idea from http://enterprisejquery.com/2010/10/how-good-c-habits-can-encourage-bad-javascript-habits-part-1/
(function( cursorManager ) {

    //From: http://www.w3.org/TR/html-markup/syntax.html#syntax-elements
    var voidNodeTags = ['AREA', 'BASE', 'BR', 'COL', 'EMBED', 'HR', 'IMG', 'INPUT', 'KEYGEN', 'LINK', 'MENUITEM', 'META', 'PARAM', 'SOURCE', 'TRACK', 'WBR', 'BASEFONT', 'BGSOUND', 'FRAME', 'ISINDEX'];

    //From: http://stackoverflow.com/questions/237104/array-containsobj-in-javascript
    Array.prototype.contains = function(obj) {
        var i = this.length;
        while (i--) {
            if (this[i] === obj) {
                return true;
            }
        }
        return false;
    }

    //Basic idea from: http://stackoverflow.com/questions/19790442/test-if-an-element-can-contain-text
    function canContainText(node) {
        if(node.nodeType == 1) { //is an element node
            return !voidNodeTags.contains(node.nodeName);
        } else { //is not an element node
            return false;
        }
    };

    function getLastChildElement(el){
        var lc = el.lastChild;
        while(lc && lc.nodeType != 1) {
            if(lc.previousSibling)
                lc = lc.previousSibling;
            else
                break;
        }
        return lc;
    }

    //Based on Nico Burns's answer
    cursorManager.setEndOfContenteditable = function(contentEditableElement)
    {

        while(getLastChildElement(contentEditableElement) &&
              canContainText(getLastChildElement(contentEditableElement))) {
            contentEditableElement = getLastChildElement(contentEditableElement);
        }

        var range,selection;
        if(document.createRange)//Firefox, Chrome, Opera, Safari, IE 9+
        {    
            range = document.createRange();//Create a range (a range is a like the selection but invisible)
            range.selectNodeContents(contentEditableElement);//Select the entire contents of the element with the range
            range.collapse(false);//collapse the range to the end point. false means collapse to end rather than the start
            selection = window.getSelection();//get the selection object (allows you to change selection)
            selection.removeAllRanges();//remove any selections already made
            selection.addRange(range);//make the range you have just created the visible selection
        }
        else if(document.selection)//IE 8 and lower
        { 
            range = document.body.createTextRange();//Create a range (a range is a like the selection but invisible)
            range.moveToElementText(contentEditableElement);//Select the entire contents of the element with the range
            range.collapse(false);//collapse the range to the end point. false means collapse to end rather than the start
            range.select();//Select the range (make it the visible selection
        }
    }

}( window.cursorManager = window.cursorManager || {}));

Usage:

var editableDiv = document.getElementById("my_contentEditableDiv");
cursorManager.setEndOfContenteditable(editableDiv);

In this way, the cursor is surely positioned at the end of the last element, eventually nested.

EDIT #1: In order to be more generic, the while statement should consider also all the other tags which cannot contain text. These elements are named void elements, and in this question there are some methods on how to test if an element is void. So, assuming that exists a function called canContainText that returns true if the argument is not a void element, the following line of code:

contentEditableElement.lastChild.tagName.toLowerCase() != 'br'

should be replaced with:

canContainText(getLastChildElement(contentEditableElement))

EDIT #2: The above code is fully updated, with every changes described and discussed

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