javascript - jQuery Set Cursor Position in Text Area

Question

How do you set the cursor position in a text field using jQuery? I've got a text field with content, and I want the users cursor to be positioned at a certain offset when they focus on the field. The code should look kind of like this:

$('#input').focus(function() {
  $(this).setCursorPosition(4);
});

What would the implementation of that setCursorPosition function look like? If you had a text field with the content abcdefg, this call would result in the cursor being positioned as follows: abcd**|**efg.

Java has a similar function, setCaretPosition. Does a similar method exist for javascript?

Update: I modified CMS's code to work with jQuery as follows:

new function($) {
  $.fn.setCursorPosition = function(pos) {
    if (this.setSelectionRange) {
      this.setSelectionRange(pos, pos);
    } else if (this.createTextRange) {
      var range = this.createTextRange();
      range.collapse(true);
      if(pos < 0) {
        pos = $(this).val().length + pos;
      }
      range.moveEnd('character', pos);
      range.moveStart('character', pos);
      range.select();
    }
  }
}(jQuery);

Answer 1

Here's a jQuery solution:

$.fn.selectRange = function(start, end) {
    if(end === undefined) {
        end = start;
    }
    return this.each(function() {
        if('selectionStart' in this) {
            this.selectionStart = start;
            this.selectionEnd = end;
        } else if(this.setSelectionRange) {
            this.setSelectionRange(start, end);
        } else if(this.createTextRange) {
            var range = this.createTextRange();
            range.collapse(true);
            range.moveEnd('character', end);
            range.moveStart('character', start);
            range.select();
        }
    });
};

With this, you can do

$('#elem').selectRange(3,5); // select a range of text
$('#elem').selectRange(3); // set cursor position

• JsFiddle
• JsBin