cursor is jumping when pressing the arrow keys

Question

I have a textbox, where a forbidden character cant be typed. #.

This works, however, when the textbox is filled in with data, and I put the focus on the middle of th

Answer 1

Javascript allows you to set the cursor position for inputs.

I found two useful functions:

• getCaretPosition - https://stackoverflow.com/a/2897229/2335291
• setCaretPosition - https://stackoverflow.com/a/512542/2335291

And the solution could look like this:

  function getCaretPosition (elem) {

    // Initialize
    var iCaretPos = 0;

    // IE Support
    if (document.selection) {

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

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

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

      // The caret position is selection length
      iCaretPos = oSel.text.length;
    }
    // Firefox support
    else if (elem.selectionStart || elem.selectionStart == '0')
      iCaretPos = elem.selectionStart;

    // Return results
    return (iCaretPos);
  }

  function setCaretPosition(elem, caretPos) {
      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();
          }
      }
  }

$('[id$=txtClient]').keyup(function () {
    EnableClientValidateButton(); // When the textbox changes, the user has the ability to validate the client
    ChangeColorClient("0"); // The color is changed to white, to notify the user the client is not validated yet.
    var $el = $('[id$=txtClient]'); // the text element to seach for forbidden characters.
    var text = $el.val(); // The value of the textbox
    text = text.split("#").join("");//remove occurances of forbidden characters, in this case #

    var pos = getCaretPosition(this);
    $el.val(text);//set it back on the element
    setCaretPosition(this, pos);
});