javascript onkeydown replace code example

Example: javascript repace enter event with another character

$.fn.replaceCharOnKeyPress = function(chr, replacement) {
    var moveCursorBy = replacement.length - chr.length;
    this.each(function() {
        $(this).keypress(function(e) {
            if (e.key == chr) {
                // IE
                if(document.selection) {
                    // Determines the selected text. If no text selected, the location of the cursor in the text is returned
                    var range = document.selection.createRange();
                    // Place the replacement on the location of the selection, and remove the data in the selection
                    range.text = replacement;
                }
                // Chrome + FF
                else if(this.selectionStart || this.selectionStart == '0') {
                    // Determines the start and end of the selection.
                    // If no text selected, they are the same and the location of the cursor in the text is returned
                    // Don't make it a jQuery obj, because selectionStart and selectionEnd isn't known.
                    var start = this.selectionStart;
                    var end = this.selectionEnd;
                    // Place the replacement on the location of the selection, and remove the data in the selection
                    $(this).val($(this).val().substring(0, start) + replacement + $(this).val().substring(end, $(this).val().length));
                    // Set the cursor back at the correct location in the text
                    this.selectionStart = start + moveCursorBy + 1;
                    this.selectionEnd = start + moveCursorBy + 1;
                }
                else {
                    // if no selection could be determined,
                    // place the replacement at the end.
                    $(this).val($(this).val() + replacement);
                }
                return false;
            }
        });
    });
    return this;
};