Get cursor position (in characters) within a text Input field_问答_开发者

How can I get the caret position from within an input field?

I have found a few bits and pieces via Google, but nothing bullet proof.

Basical开发者_StackOverflow中文版ly something like a jQuery plugin would be ideal, so I could simply do

$("#myinput").caretPosition()

Easier update:

Use field.selectionStart example in this answer.

Thanks to @commonSenseCode for pointing this out.

Old answer:

Found this solution. Not jquery based but there is no problem to integrate it to jquery:

/*
** Returns the caret (cursor) position of the specified text field (oField).
** Return value range is 0-oField.value.length.
*/
function doGetCaretPosition (oField) {

  // Initialize
  var iCaretPos = 0;

  // IE Support
  if (document.selection) {

    // Set focus on the element
    oField.focus();

    // To get cursor position, get empty selection range
    var oSel = document.selection.createRange();

    // Move selection start to 0 position
    oSel.moveStart('character', -oField.value.length);

    // The caret position is selection length
    iCaretPos = oSel.text.length;
  }

  // Firefox support
  else if (oField.selectionStart || oField.selectionStart == '0')
    iCaretPos = oField.selectionDirection=='backward' ? oField.selectionStart : oField.selectionEnd;

  // Return results
  return iCaretPos;
}

Use selectionStart. It is compatible with all major browsers.

document.getElementById('foobar').addEventListener('keyup', e => {
  console.log('Caret at: ', e.target.selectionStart)
})

<input id="foobar" />

This works only when no type is defined or type="text" or type="textarea" on the input.

I've wrapped the functionality in bezmax's answer into jQuery if anyone wants to use it.

(function($) {
    $.fn.getCursorPosition = function() {
        var input = this.get(0);
        if (!input) return; // No (input) element found
        if ('selectionStart' in input) {
            // Standard-compliant browsers
            return input.selectionStart;
        } else if (document.selection) {
            // IE
            input.focus();
            var sel = document.selection.createRange();
            var selLen = document.selection.createRange().text.length;
            sel.moveStart('character', -input.value.length);
            return sel.text.length - selLen;
        }
    }
})(jQuery);

Got a very simple solution. Try the following code with verified result-

<html>
<head>
<script>
    function f1(el) {
    var val = el.value;
    alert(val.slice(0, el.selectionStart).length);
}
</script>
</head>
<body>
<input type=text id=t1 value=abcd>
    <button onclick="f1(document.getElementById('t1'))">check position</button>
</body>
</html>

I'm giving you the fiddle_demo

There is now a nice plugin for this: The Caret Plugin

Then you can get the position using $("#myTextBox").caret() or set it via $("#myTextBox").caret(position)

   (function($) {
    $.fn.getCursorPosition = function() {
        var input = this.get(0);
        if (!input) return; // No (input) element found
        if (document.selection) {
            // IE
           input.focus();
        }
        return 'selectionStart' in input ? input.selectionStart:'' || Math.abs(document.selection.createRange().moveStart('character', -input.value.length));
     }
   })(jQuery);

There are a few good answers posted here, but I think you can simplify your code and skip the check for inputElement.selectionStart support: it is not supported only on IE8 and earlier (see documentation) which represents less than 1% of the current browser usage.

var input = document.getElementById('myinput'); // or $('#myinput')[0]
var caretPos = input.selectionStart;

// and if you want to know if there is a selection or not inside your input:

if (input.selectionStart != input.selectionEnd)
{
    var selectionValue =
    input.value.substring(input.selectionStart, input.selectionEnd);
}

Perhaps you need a selected range in addition to cursor position. Here is a simple function, you don't even need jQuery:

function caretPosition(input) {
    var start = input[0].selectionStart,
        end = input[0].selectionEnd,
        diff = end - start;

    if (start >= 0 && start == end) {
        // do cursor position actions, example:
        console.log('Cursor Position: ' + start);
    } else if (start >= 0) {
        // do ranged select actions, example:
        console.log('Cursor Position: ' + start + ' to ' + end + ' (' + diff + ' selected chars)');
    }
}

Let's say you wanna call it on an input whenever it changes or mouse moves cursor position (in this case we are using jQuery .on()). For performance reasons, it may be a good idea to add setTimeout() or something like Underscores _debounce() if events are pouring in:

$('input[type="text"]').on('keyup mouseup mouseleave', function() {
    caretPosition($(this));
});

Here is a fiddle if you wanna try it out: https://jsfiddle.net/Dhaupin/91189tq7/

const inpT = document.getElementById("text-box");
const inpC = document.getElementById("text-box-content");
// swch gets  inputs .
var swch;
// swch  if corsur is active in inputs defaulte is false .
var isSelect = false;

var crnselect;
// on focus
function setSwitch(e) {
  swch = e;
  isSelect = true;
  console.log("set Switch: " + isSelect);
}
// on click ev
function setEmoji() {
  if (isSelect) {
    console.log("emoji added :)");
    swch.value += ":)";
    swch.setSelectionRange(2,2 );
    isSelect = true;
  }

}
// on not selected on input . 
function onout() {
  // الافنت  اون كي اب 
  crnselect = inpC.selectionStart;
  
  // return input select not active after 200 ms .
  var len = swch.value.length;
  setTimeout(() => {
   (len == swch.value.length)? isSelect = false:isSelect = true;
  }, 200);
}

<h1> Try it !</h1>
    
		<input type="text" onfocus = "setSwitch(this)" onfocusout = "onout()" id="text-box" size="20" value="title">
		<input type="text" onfocus = "setSwitch(this)"  onfocusout = "onout()"  id="text-box-content" size="20" value="content">
<button onclick="setEmoji()">emogi :) </button>

The solution is .selectionStart:

var input = document.getElementById('yourINPUTid');
input.selectionEnd = input.selectionStart = yourDESIREDposition;
input.focus();

If .selectionEnd is not assiged, some text (S-->E) will be selected.

.focus() is required when the focus is lost; when you trigger your code (onClick).

I only tested this in Chrome.

If you want more complicated solutions, you have to read the other answers.

Get cursor position (in characters) within a text Input field

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