The reason it is doing that is because your .php script tells it to. Right now you are requiring all fields to be filled in. Originally it was just name, message and email that were required, but when you added occupation, companyname, postcode, contactnumber and the rest to that list, everything now needs to be filled in. If it's not, it will print "Error: all fields are required" The email address error comes a little later in your .php. If it is left blank the error displays as invalid due to the code toward the middle of your .php. If the email is wrong or missing, it will print "Error: Invalid email address". You can make your error page graphically interesting if you like by adding the html design elements around the line... <?php echo nl2br($errors); ?> That .php snippet is what's responsible for printing out the actual error messages, the html stuff around it is responsible for the design of the page. You can treat those <html>, <head> and <body> tags just like any other page on your site and add in whatever you like. I suspect the pop-up alert is being caused by a javascript on the page with the form. Unfortunately, I can't view your site for some reason to tell you where it is, I still get a "Server not found" error.
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