Online Calculator "How much mortgage/loan can you afford?" - PHP, Ajax, JavaScript and Bootstrap -- 2

We are looking for someone who can do some coding for us. Take a look at [login to view URL] (maybe have it translated on the fly with Google Chrome). We need an online calculator where the user can calculate the aprox amount of mortage / loan he can afford for real estate. The user enters his current cold rent and the amount of money he has in his savings account (equity capital). The calculator then does the math: maximum loan amount, notary and land registry costs, intrest etc. (the intrest for this calculator is fixed) calculation formulas will be provided (very simple!) In the attached Screenshots I highlighted the parts of the page we need. No header, no footer, no SEO, just the form and the calculator itself since we will use the code within a Joomla Page (SP Page Builder [login to view URL] ). This calculator has to ... ... support current PHP Version ... do its work on the fly, the user should not need to klick a button or go to an other page to see the results of the calculation (PHP / Ajax, I'm not sure about JavaScript) ... support all current browsers and devices (Bootstrap?!) ... has a [login to view URL] or smth like that so we can easily chance parameters on our own (f.e. interest-rate) ... of course, needs to check the entered dato (f.e. letters in the field for cold rent doesn't make any sense) It's pretty mutch the calculator you can see on the link above. DIFFERENT from that should be: After the user got his calculation, he should be provided an other form where he can enter contact details so he can ask the site owner to come back to him on this matter: First name* / Surname / E-Mail** / Phone** * mandatory field ** user can choose between providing email or Phone - one of them is a mandatory field Once the user fills out the "contact-form" one or two E-Mails need to be send: #1 E-Mail to the user confirming the site owner will get back to him in this matter (if the user provided an E-Mailadress) #2 E-Mail to the site owner with the calculation / data the user entered and the contact details of the user This is one (the simplest one) of 3-5 online calculators we need to be done. So we are looking for someone who is interested in getting hired again for the other calculators which we want to be in the same "look and feel".