<html> <head> <script type="text/javascript"> function insert(el) { if (el.setSelectionRange){ el.focus(); el.value = el.value.substring(0,el.selectionStart) + "amr" + el.value.substring(el.selectionStart,el.selectionEnd) + el.value.substring(el.selectionEnd,el.value.length); } else if (document.selection && document.selection.createRange) { el.focus(); var range = document.selection.createRange(); range.text = "amr" + range.text; } } </script> </head> <body> <form> <input type="text" name="ahmed"> <input type="button" value="add" onclick="insert(this.form.ahmed,'add')"> </form> </body> </html>