function clickclear(thisfield, defaulttext) {
		if (thisfield.value == defaulttext) {
		thisfield.value = "";
		}
		}
		
		function clearField(field, hiddenfield)
		{
			document.getElementById(field).value = "";
			document.getElementById(hiddenfield).value = "";
		}
		

		$(document).ready(function() {
		   for(i=0; i<document.networkUpdateForm.elements.length; i++)
			{
				if(document.networkUpdateForm.elements[i].name.search('postcode') != -1 )
				{
					document.getElementById('postcodes').value = document.networkUpdateForm.elements[i].value;
					return;
				}
			}
		 });

		
		
		
		
		
		
		function addPostcode(field, hiddenfield){
			var postcodeValue = document.getElementById(field).value;
			postcodeValue = postcodeValue.toUpperCase();
			document.getElementById('postcodeErrors').innerHTML = "";
			addPostcodetoField(field, postcodeValue, hiddenfield);
		}
		
		function addPostcodetoField(field, postcodeValue, hiddenfield)
		{
			if(document.getElementById('postcodes').value == '')
			{
				document.getElementById(hiddenfield).value = '';
			}
			
			//check for multiple postcodes
			if(postcodeValue.search(",") != -1)
			{
				var postcodeArray = postcodeValue.split(",");
				for(var i in postcodeArray)
				{
					addPostcodetoField(field, postcodeArray[i], hiddenfield);
				}
			
			}
			else
			{
				var postcodes = document.getElementById(hiddenfield).value;
				postcodeValue = postcodeValue.replace(" ","");
				if(validatePostCode(postcodeValue) == null)
				{
					showError("Please enter a valid postcode area e.g. SW18");
				}
				else
				{
					var trimmedPostcode;
					
					if(postcodeValue.length > 4)
					{
						postcodeValue = postcodeValue.replace(" ","");
						trimmedPostcode = postcodeValue.substring(0,postcodeValue.length-3);
					}
					else
					{
						trimmedPostcode = postcodeValue;
					}
					if(postcodeMaintenance(trimmedPostcode))
					{
						if(postcodes != null && postcodes != "")
						{
							if(postcodes.search(trimmedPostcode+",") != -1)
							{
								showError('You have already entered this postcode');
								return;
							}
							
							var postcodeArray = postcodes.split(",");
							if (postcodeArray.length > 3)
							{
									showError("Please enter a maximum of 4 postcodes");
							}
							else
							{
									if(postcodes == trimmedPostcode)
									{
										showError('You have already entered this postcode');
										return;
									}
									document.getElementById(hiddenfield).value = postcodes + ", "+trimmedPostcode;
									document.getElementById('postcodes').value = postcodes + ", "+trimmedPostcode;
									document.getElementById(field).value = '';
							}
						}
						else
						{
							document.getElementById(hiddenfield).value = trimmedPostcode;
							document.getElementById('postcodes').value = trimmedPostcode;
							document.getElementById(field).value = '';
						}
					}
					else
					{
						showError("There are no planned upgrades in your area(s)");
					}
				}
			}

		}
		
		
		function showError(message)
		{
			document.getElementById('postcodeErrors').innerHTML = message;
		}

		function validatePostCode( postCode )
		{
			var regexS_Full = "[a-zA-Z]{1,2}[0-9]{1,2}[0-9a-zA-Z]?[0-9][a-zA-Z]{2}$";
			var regexS_Half = "[a-zA-Z]{1,2}[0-9]{1,2}[a-zA-Z]?$";
			var regex_Full = new RegExp( regexS_Full );
			var regex_Half = new RegExp( regexS_Half );
			var cleanPostCode = postCode.replace(new RegExp(" ", "g" ), '');
		  var results1 = regex_Full.exec( cleanPostCode );
		  var results2 = regex_Half.exec( cleanPostCode );
		  if( results2 == null && results1 == null )
				return null;
			else
			  return 'valid';
		}