http://www.codewrapper.com/Snippets/View/40/jquery-insert-text-at-the-current-cursor-position-in-textbox
$.fn.insertAtCaret = function (myValue) {
return this.each(function(){
//IE support
if (document.selection) {
this.focus();
sel = document.selection.createRange();
sel.text = myValue;
this.focus();
}
//MOZILLA/NETSCAPE support
else if (this.selectionStart || this.selectionStart == '0') {
var startPos = this.selectionStart;
var endPos = this.selectionEnd;
var scrollTop = this.scrollTop;
this.value = this.value.substring(0, startPos)
+ myValue
+ this.value.substring(endPos, this.value.length);
this.focus();
this.selectionStart = startPos + myValue.length;
this.selectionEnd = startPos + myValue.length;
this.scrollTop = scrollTop;
} else {
this.value += myValue;
this.focus();
}
});
};