function validatetank( form_valid )
{

if( form_valid.client_name.value == "" ) {
		alert("Please enter Client Name");
			form_valid.client_name.focus();
			return false;
		}

if( form_valid.contact_name.value == "" ) {
		alert("Please enter Contact name");
			form_valid.contact_name.focus();
			return false;
		}
		
else if
 		( form_valid.email_address.value == "" ) {
			alert("Please enter Email Address");
			form_valid.email_address.focus();
			return false;
		}

else if(!(/^\w+([\.-]?\w+)*@\w+([\.-]?\w+)*(\.\w{2,3})+$/.test(form_valid.email_address.value))) {
			alert("Please enter valid email address");
			form_valid.email_address.focus();
			return false;
		}

else if
 		( form_valid.phone.value == "" ) {
			alert("Please enter Telephone No.");
			form_valid.phone.focus();
			return false;
		}
else if
 		( form_valid.fax.value == "" ) {
			alert("Please enter Fax No.");
			form_valid.fax.focus();
			return false;
		}
else if
 		( form_valid.delivery_date.value == "" ) {
			alert("Please enter Delivery Date");
			form_valid.delivery_date.focus();
			return false;
		}
else if
 		( form_valid.delivery_address.value == "" ) {
			alert("Please enter Delivery Address");
			form_valid.delivery_address.focus();
			return false;
		}
else if
 		( form_valid.material_required.value == "" ) {
			alert("Please Select Material Required");
			form_valid.material_required.focus();
			return false;
		}
else if
 		( form_valid.system_life.value == "" ) {
			alert("Please enter System Life");
			form_valid.system_life.focus();
			return false;
		}
else if
 		( form_valid.ballast_time.value == "" ) {
			alert("Please enter Ballast Voyage Time");
			form_valid.ballast_time.focus();
			return false;
		}
else if
 		( form_valid.ballast_ratio.value == "" ) {
			alert("Please enter Ballast Ratio");
			form_valid.ballast_ratio.focus();
			return false;
		}

else if
 		( form_valid.tank_capacity.value == "" ) {
			alert("Please enter Tank Capacity");
			form_valid.tank_capacity.focus();
			return false;
		}

else if
 		( form_valid.coating_breakdown.value == "" ) {
			alert("Please enter Tank Coating Breakdown");
			form_valid.coating_breakdown.focus();
			return false;
		}

else if
 		( form_valid.design_required.value == "" ) {
			alert("Please Select Design Required.");
			form_valid.design_required.focus();
			return false;
		}
else if
 		( form_valid.survey_required.value == "" ) {
			alert("Please Select Survey Required.");
			form_valid.survey_required.focus();
			return false;
		}

}