Add specialchars and captcha to emailscript

I need a expert how modificate a ajax email script

this wre the requirements

make it secure for hackers

add a captcha

add the possibility to display html specialchars like this àáâãäçèéêëìíñòóôõö correct in the received emails

also there is an issue in the received emails dont show the name phone adress when i get the mail it should show like this

name:

adress:

phone:

email:

subject:

message:

-------------------------------------------

without the adress the other fields need be required

i attach the ajaxscript i use now i dont want change to a other please keep the strukture because i include this in a template phpfile ==> template file

AJAX JavaScript PHP

Project ID: #379163

About the project