Hello

This might be a simple question, but it is stretching my mind!

I have a HTML page and clicking on a link brings up a light-box. The lightbox is a form linked to three CDD files and a PHP files which processes the form in the background when the site visitor clicks 'submit'.

I am proposing to add another field to the form which will alllow visitors to attach files to their message.

I have to be a bit careful how I code this because the form also links to three JavaScript files and everything interrelates.

The three CSS files are as follows:

contact.css:

Code:
body {height:100%; margin:0;}

/* Overlay */
#contact-overlay {background-color:#000; cursor:wait;}

/* Container */
#contact-container {width:430px; font-family:Verdana, Arial; font-size:12px; text-align:left;}
#contact-container .contact-content {background-color:#333; color:#ddd; height:40px;}
#contact-container h1 {color:#F6E095; margin:0; padding:0 0 6px 12px; font-size:1.2em; text-align:left;}
#contact-container .contact-loading {position:absolute; background:url(../img/contact/loading.gif) no-repeat; z-index:8000; height:55px; width:54px; margin:-14px 0 0 170px; padding:0;}
#contact-container .contact-message {text-align:center;}
#contact-container .contact-error {width:92%; font-size:.8em; background:#000; border:2px solid #ccc; font-size:0.8em; font-weight:bold; margin:0 auto; padding:2px;}
#contact-container br {clear:both;}
#contact-container form {padding:0; margin:0;}
#contact-container label {clear:left; display:block; width:100px; float:left; text-align:right; padding-right:4px; font-weight:bold;}
#contact-container .contact-input {font-family:Verdana, Arial; float:left; padding:2px; margin:2px; background:#eee; border:1px solid #fff; width:300px;}
#contact-container textarea {height:114px; font-size:.9em;}
#contact-container .contact-cc {font-size:.9em; cursor:default;}
#contact-container .contact-top {height:13px; background:url(../img/contact/form_top.gif) no-repeat; padding:0; margin:0;}
#contact-container .contact-bottom {height:13px; background:url(../img/contact/form_bottom.gif) no-repeat; font-size:.7em; text-align:center;}
#contact-container .contact-bottom a,
#contact-container .contact-bottom a:link,
#contact-container .contact-bottom a:active,
#contact-container .contact-bottom a:visited {position:relative; top:-4px; text-decoration:none; color:#666;}
#contact-container .contact-bottom a:hover {color:#888;}
#contact-container .contact-button {margin:4px 0 0 4px; cursor:pointer; height:24px; border:0; font-size:1em; font-weight:bold; color:#fff; text-align:center; vertical-align:middle;}
#contact-container .contact-send {width:50px; background:url(../img/contact/send.png) no-repeat;}
#contact-container .contact-cancel {width:65px; background:url(../img/contact/cancel.png) no-repeat;}
#contact-container a.modal-close,
#contact-container a.modal-close:link,
#contact-container a.modal-close:active,
#contact-container a.modal-close:visited {text-decoration:none; font-weight:bold; font-size:1.2em; position:absolute; top:-4px; right:6px; color:#999;}
#contact-container a.modal-close:hover {color:#9bb3b3;}
default.css

Code:
*{
	margin:0;
	padding:0;
}
body{
	margin:30px 0 30px 0;
	text-align:center;
	background-color:#62E122;
	font-size:80%;
	font-family:"Lucida Grande", Tahoma, sans-serif;
}
p{
	margin:0 0 1em 0;
}
a{
	color:green;
}
a img{
	border:none !important;
}
#container{
	margin:0 auto;
	width:500px;
	padding:40px;
	text-align:left;
	background-color:#fff;
}
#container ul{
	text-align:center;
	margin:0 0 30px 0;
	list-style:none;
}
#container ul a{
	border:1px solid #eee;
	background-color:#f5f5f5;
	color:#444;
	font-size:1.5em;
	line-height:2em;
	padding:20px;
	margin:0 0 20px 0;
	display:block;
}
#container ul a:hover{
	border:1px solid #B5DF99;
	background-color:#CDEFB6;
	color:#358610;
}

#lightbox h2{
	margin:0 0 1em 0;
}
#lightbox h3{
	color:#FF713F;
}
#lightbox.done p{
	color:#333;
}

#form{
	text-align:left;
	margin:25px;
}
#form ul{
	list-style:none;
}
#form li{
	margin:0 0 1em 0;
}
#form textarea{
	width:100%;
	height:150px;
}

#definition{
	margin:25px;
}
.highlight{
	background-color:#FEFFAF;
}
lightbox.css

Code:
#lightbox{
	display:none;
	position: absolute;
	top:50%;
	left:50%;
	z-index:9999;
	width:500px;
	height:400px;
	margin:-220px 0 0 -250px;
	border:1px solid #fff;
	background:#FDFCE9;
	text-align:left;
}
#lightbox[id]{
	position:fixed;
}

#overlay{
	display:none;
	position:absolute;
	top:0;
	left:0;
	width:100%;
	height:100%;
	z-index:5000;
	background-color:#000;
	-moz-opacity: 0.8;
	opacity:.80;
	filter: alpha(opacity=80);
}
#overlay[id]{
	position:fixed;
}

#lightbox.done #lbLoadMessage{
	display:none;
}
#lightbox.done #lbContent{
	display:block;
}
#lightbox.loading #lbContent{
	display:none;
}
#lightbox.loading #lbLoadMessage{
	display:block;
}

#lightbox.done img{
	width:100%;
	height:100%;
}
The question I have is where do I begin to add the new form field!?

Many thanks.

Steve