Set keyboard caret position in html textbox

Question

Does anybody know how to move the keyboard caret in a textbox to a particular position?

For example, if a text-box (e.g. input element, not text-area) has 50 characters in it and I want to position the caret before character 20, how would I go about it?

This is in differentiation from this question: jQuery Set Cursor Position in Text Area , which requires jQuery.

Answer 1

Excerpted from Josh Stodola's Setting keyboard caret Position in a Textbox or TextArea with Javascript

A generic function that will allow you to insert the caret at any position of a textbox or textarea that you wish:

function setCaretPosition(elemId, caretPos) {
    var elem = document.getElementById(elemId);

    if(elem != null) {
        if(elem.createTextRange) {
            var range = elem.createTextRange();
            range.move('character', caretPos);
            range.select();
        }
        else {
            if(elem.selectionStart) {
                elem.focus();
                elem.setSelectionRange(caretPos, caretPos);
            }
            else
                elem.focus();
        }
    }
}

The first expected parameter is the ID of the element you wish to insert the keyboard caret on. If the element is unable to be found, nothing will happen (obviously). The second parameter is the caret positon index. Zero will put the keyboard caret at the beginning. If you pass a number larger than the number of characters in the elements value, it will put the keyboard caret at the end.

Tested on IE6 and up, Firefox 2, Opera 8, Netscape 9, SeaMonkey, and Safari. Unfortunately on Safari it does not work in combination with the onfocus event).

An example of using the above function to force the keyboard caret to jump to the end of all textareas on the page when they receive focus:

function addLoadEvent(func) {
    if(typeof window.onload != 'function') {
        window.onload = func;
    }
    else {
        if(func) {
            var oldLoad = window.onload;

            window.onload = function() {
                if(oldLoad)
                        oldLoad();

                func();
            }
        }
    }
}

// The setCaretPosition function belongs right here!

function setTextAreasOnFocus() {
/***
 * This function will force the keyboard caret to be positioned
 * at the end of all textareas when they receive focus.
 */
    var textAreas = document.getElementsByTagName('textarea');

    for(var i = 0; i < textAreas.length; i++) {
        textAreas[i].onfocus = function() {
            setCaretPosition(this.id, this.value.length);
        }
    }

    textAreas = null;
}

addLoadEvent(setTextAreasOnFocus);

Answer 2

The link in the answer is broken, this one should work (all credits go to blog.vishalon.net):

http://snipplr.com/view/5144/getset-cursor-in-html-textarea/

In case the code gets lost again, here are the two main functions:

function doGetCaretPosition(ctrl)
{
 var CaretPos = 0;

 if (ctrl.selectionStart || ctrl.selectionStart == 0)
 {// Standard.
  CaretPos = ctrl.selectionStart;
 }
 else if (document.selection)
 {// Legacy IE
  ctrl.focus ();
  var Sel = document.selection.createRange ();
  Sel.moveStart ('character', -ctrl.value.length);
  CaretPos = Sel.text.length;
 }

 return (CaretPos);
}


function setCaretPosition(ctrl,pos)
{
 if (ctrl.setSelectionRange)
 {
  ctrl.focus();
  ctrl.setSelectionRange(pos,pos);
 }
 else if (ctrl.createTextRange)
 {
  var range = ctrl.createTextRange();
  range.collapse(true);
  range.moveEnd('character', pos);
  range.moveStart('character', pos);
  range.select();
 }
}

Answer 3

Since I actually really needed this solution, and the typical baseline solution (focus the input - then set the value equal to itself) doesn't work cross-browser, I spent some time tweaking and editing everything to get it working. Building upon @kd7's code here's what I've come up with.

Enjoy! Works in IE6+, Firefox, Chrome, Safari, Opera

Cross-browser caret positioning technique (example: moving the cursor to the END)

// ** USEAGE ** (returns a boolean true/false if it worked or not)
// Parameters ( Id_of_element, caretPosition_you_want)

setCaretPosition('IDHERE', 10); // example

The meat and potatoes is basically @kd7's setCaretPosition, with the biggest tweak being if (el.selectionStart || el.selectionStart === 0), in firefox the selectionStart is starting at 0, which in boolean of course is turning to False, so it was breaking there.

In chrome the biggest issue was that just giving it .focus() wasn't enough (it kept selecting ALL of the text!) Hence, we set the value of itself, to itself el.value = el.value; before calling our function, and now it has a grasp & position with the input to use selectionStart.

function setCaretPosition(elemId, caretPos) {
    var el = document.getElementById(elemId);

    el.value = el.value;
    // ^ this is used to not only get "focus", but
    // to make sure we don't have it everything -selected-
    // (it causes an issue in chrome, and having it doesn't hurt any other browser)

    if (el !== null) {

        if (el.createTextRange) {
            var range = el.createTextRange();
            range.move('character', caretPos);
            range.select();
            return true;
        }

        else {
            // (el.selectionStart === 0 added for Firefox bug)
            if (el.selectionStart || el.selectionStart === 0) {
                el.focus();
                el.setSelectionRange(caretPos, caretPos);
                return true;
            }

            else  { // fail city, fortunately this never happens (as far as I've tested) :)
                el.focus();
                return false;
            }
        }
    }
}

Answer 4

I found an easy way to fix this issue, tested in IE and Chrome:

function setCaret(elemId, caret)
 {
   var elem = document.getElementById(elemId);
   elem.setSelectionRange(caret, caret);
 }

Pass text box id and caret position to this function.

Answer 5

I've adjusted the answer of kd7 a little bit because elem.selectionStart will evaluate to false when the selectionStart is incidentally 0.

function setCaretPosition(elem, caretPos) {
    var range;

    if (elem.createTextRange) {
        range = elem.createTextRange();
        range.move('character', caretPos);
        range.select();
    } else {
        elem.focus();
        if (elem.selectionStart !== undefined) {
            elem.setSelectionRange(caretPos, caretPos);
        }
    }
}

Answer 6

If you need to focus some textbox and your only problem is that the entire text gets highlighted whereas you want the caret to be at the end, then in that specific case, you can use this trick of setting the textbox value to itself after focus:

$("#myinputfield").focus().val($("#myinputfield").val());

Answer 7

I would fix the conditions like below:

function setCaretPosition(elemId, caretPos)
{
 var elem = document.getElementById(elemId);
 if (elem)
 {
  if (typeof elem.createTextRange != 'undefined')
  {
   var range = elem.createTextRange();
   range.move('character', caretPos);
   range.select();
  }
  else
  {
   if (typeof elem.selectionStart != 'undefined')
    elem.selectionStart = caretPos;
   elem.focus();
  }
 }
}

Answer 8

function SetCaretEnd(tID) {
    tID += "";
    if (!tID.startsWith("#")) { tID = "#" + tID; }
    $(tID).focus();
    var t = $(tID).val();
    if (t.length == 0) { return; }
    $(tID).val("");
    $(tID).val(t);
    $(tID).scrollTop($(tID)[0].scrollHeight); }

Answer 9

HTMLInputElement.setSelectionRange( selectionStart, selectionEnd );

// References
var e = document.getElementById( "helloworldinput" );

// Move caret to beginning on focus
e.addEventListener( "focus", function( event )
{
    // References
    var e = event.target;

    // Action
    e.setSelectionRange( 0, 0 );            // Doesn’t work for focus event
    
    window.setTimeout( function()
    {
        e.setSelectionRange( 0, 0 );        // Works
        //e.setSelectionRange( 1, 1 );      // Move caret to second position
        //e.setSelectionRange( 1, 2 );      // Select second character

    }, 0 );

}, false );

Browser compatibility (only for types: text, search, url, tel and password): https://developer.mozilla.org/en-US/docs/Web/API/HTMLInputElement/setSelectionRange#Specifications

Answer 10

<!DOCTYPE html>
<html>
<head>
<title>set caret position</title>
<script type="application/javascript">
//<![CDATA[
window.onload = function ()
{
 setCaret(document.getElementById('input1'), 13, 13)
}

function setCaret(el, st, end)
{
 if (el.setSelectionRange)
 {
  el.focus();
  el.setSelectionRange(st, end);
 }
 else
 {
  if (el.createTextRange)
  {
   range = el.createTextRange();
   range.collapse(true);
   range.moveEnd('character', end);
   range.moveStart('character', st);
   range.select();
  }
 }
}
//]]>
</script>
</head>
<body>

<textarea id="input1" name="input1" rows="10" cols="30">Happy kittens dancing</textarea>

<p>&nbsp;</p>

</body>
</html>

Answer 11

Here's a variation of the accepted answer:

• allows to specify the target element by passing any valid CSS selector OR by providing the element itself
• written in TypeScript
• class-based
• SRP implemented by splitting the solution into a number of smaller functions
• throws custom errors

// CaretPositioner.ts

class ElementNotFoundError extends Error {}
class InvalidArgumentValueError extends Error {}

type HTMLInputOrTextAreaElement = HTMLInputElement | HTMLTextAreaElement

class CaretPositioner {
  public static setCaretPosition (
    element: HTMLInputOrTextAreaElement,
    caretPosition: number,
  ): void

  public static setCaretPosition (
    selector: string,
    caretPosition: number,
  ): void

  public static setCaretPosition (
    elementOrSelector: HTMLInputOrTextAreaElement | string,
    caretPosition: number,
  ): void {
    const element: HTMLInputOrTextAreaElement =
      CaretPositioner.determineElement(elementOrSelector)

    CaretPositioner._setCaretPosition(element, caretPosition)
  }

  private static determineElement (
    elementOrSelector: HTMLInputOrTextAreaElement | string,
  ): HTMLInputOrTextAreaElement {
    if (
      (elementOrSelector instanceof HTMLInputElement) ||
      (elementOrSelector instanceof HTMLTextAreaElement)
    ) {
      return elementOrSelector
    } else if (CaretPositioner.isValidCssSelector(elementOrSelector)) {
      return CaretPositioner.getInputElementBySelector(elementOrSelector)
    } else {
      throw new InvalidArgumentValueError()
    }
  }

  private static isValidCssSelector (subject: unknown): boolean {
    return typeof subject === 'string' &&
      subject.length > 0
  }

  private static getInputElementBySelector (
    selector: string,
  ): HTMLInputOrTextAreaElement {
    const element = document.querySelector(selector)

    if (
      !(element instanceof HTMLInputElement) &&
      !(element instanceof HTMLTextAreaElement)
    ) {
      throw new ElementNotFoundError('element')
    }

    return element
  }

  private static _setCaretPosition (
    element: HTMLInputOrTextAreaElement,
    caretPosition: number,
  ): void {
    element.focus()
    element.setSelectionRange(caretPosition, caretPosition)
  }
}

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I wanted to add this piece as a comment to the aforementioned answer, but I have not enough reputation points to do so.