JavaScript - Fill Field With Day Of Week Field Upon User Selected Date.

function validateCheckbox() {
if(document.forms["form1"].sales.checked) {
  if(document.forms["form1"].telephone.value.length < 12) { // xxx-xxx-xxxx
    return false	;
   }
  else {
    return true;
   }
}
}

function MM_validateForm() { //v4.0
  if (document.getElementById){
    var i,p,q,nm,test,num,min,max,errors='',args=MM_validateForm.arguments;
    for (i=0; i<(args.length-2); i+=3) { test=args[i+2]; val=document.getElementById(args[i]);
      if (val) { nm=val.name; if ((val=val.value)!="") {
        if (test.indexOf('isEmail')!=-1) { p=val.indexOf('@');
          if (p<1 || p==(val.length-1)) errors+='- '+nm+' must contain an e-mail address.\n';
        } else if (test!='R') { num = parseFloat(val);
          if (isNaN(val)) errors+='- '+nm+' must contain a number.\n';
          if (test.indexOf('inRange') != -1) { p=test.indexOf(':');
            min=test.substring(8,p); max=test.substring(p+1);
            if (num<min || max<num) errors+='- '+nm+' must contain a number between '+min+' and '+max+'.\n';
      } } } else if (test.charAt(0) == 'R') errors += '- '+nm+' is required.\n'; }
    }
	 if(!validateCheckbox()) {
       errors+="If checkbox checked, please include telephone number";
     }
if (errors) alert('The following error(s) occurred:\n'+errors);
    document.MM_returnValue = (errors == '');
} }




//-->

	    if (frm.date.value [is previous from] $todays_date)
    {
        alert('Date can't be previous from today')
        frm.date.focus()
        return false
    }

<?php
	
	class MagentoTeam_Ddc_Block_Form extends Mage_Checkout_Block_Onepage_Abstract{
		
		protected $delivery_date;
		protected $customer_comment;
		
		public function getDeliveryDate(){
			
			if(is_null($this->delivery_date)){
				$this->delivery_date = $this->getCheckout()->getQuote()->getDeliveryDate();
			
			}
			return $this->delivery_date;
		}
		
		
		public function getCustomerComment(){
			
			if(is_null($this->customer_comment)){
				$this->customer_comment = $this->getCheckout()->getQuote()->getCustomerComment();
			}
			return $this->customer_comment;
		}
		public function getConfigData($node){
			
			return Mage::getStoreConfig(sprintf('magentoteam_ddc/%s', $node));
			
		}
		public function getFirstDay(){
			
			return intval(Mage::getStoreConfig('general/locale/firstday'));
			
		}
	}

<label>First Name<a href"#">click</a></label>
<input class="text-input medium-input" type="text" id="medium-input" name="FirstName" />
<span class="input-notification success png_bg">Successful message</span>

<script>
        $("a").click(function () {
          $("tab2").fadeIn(3000, function () {
            $("span").fadeIn(100);
          });
          return false;
        }); 

      </script>

                        //check if over 18
			
	         function overAge(){
				var age;
				var input = document.forms[0].birthDate.value;
				var pyear = parseInt(input.substring(6,10));
				var pmonth = parseInt(input.substring(0,2)) - 1;
				var pday = parseInt(input.substring(3,5));
	
				if ( month < pmonth ){
					age = year - pyear - 1;
				}
				else if ( month > pmonth ){
					age = year - pyear;
				}
				else if ( month == pmonth ){
					if ( day < pday ){
						age = year - pyear - 1;
					}
					else if ( day > pday ){
						age = year - pyear;
					}
					else if ( day == pday ){
						age = year - pyear;
					}
				}
				if(age < 18){
					window.alert('Attention: Under 18!');
					valid=false;
					return valid;
				}
                          }

Date of Birth: <br/>
	<input type = "text" name = "date" value = "(mm/dd/yyyy)"/>

<script language="javascript">

fields = 1;

function addMore() {

if (fields = 1) {

document.getElementById('addedMore').innerHTML = "<input type='text' name='field2' size='25' /> <span>Field 2.</span>";

fields = 2;

} else if (fields = 2) {

document.getElementById('addedMore').innerHTML = "<input type='text' name='field3' size='25' /> <span>Field 3.</span>";
fields = 3;

} else {

document.getElementById('addedMore').innerHTML = "Only 3 fields are allowed.";
document.form.add.disabled=true;

}

}

</script>

<input type="text" name="field1" size="25" /> <span>Field 1.</span>
<div id="addedMore"></div>
<p class="addMore"><form name="add"><a onclick="addMore()">Add another field.</a></form></p>