Validar campos no Formulario.php

Olá pessoal, seguinte, tenho uma pagina em php com o nome licitacao.php, nela existe três tipo de visualizações, mais o que eu to querendo agora e o seguinte, se falta um campo dos obrigatorios não enviar para o banco.

Como faço isso, em que parte do corpo devo colocar alguma aplicação em JS....

O codigo é esse, vou colocar ele todo.....

<?php require_once('Connections/cigas.php'); ?>
<?php
if (!isset($_SESSION)) {
 session_start();
}
$MM_authorizedUsers = "adm";
$MM_donotCheckaccess = "false";

// *** Restrict Access To Page: Grant or deny access to this page

function isAuthorized($strUsers, $strGroups, $UserName, $UserGroup) {
 // For security, start by assuming the visitor is NOT authorized.
 $isValid = False;

 // When a visitor has logged into this site, the Session variable MM_Username set equal to their username.
 // Therefore, we know that a user is NOT logged in if that Session variable is blank.
 if (!empty($UserName)) {
	// Besides being logged in, you may restrict access to only certain users based on an ID established when they login.
	// Parse the strings into arrays.
	$arrUsers = Explode(",", $strUsers);
	$arrGroups = Explode(",", $strGroups);
	if (in_array($UserName, $arrUsers)) {
 $isValid = true;
	}
	// Or, you may restrict access to only certain users based on their username.
	if (in_array($UserGroup, $arrGroups)) {
 $isValid = true;
	}
	if (($strUsers == "") && false) {
 $isValid = true;
	}
 }
 return $isValid;
}

$MM_restrictGoTo = "intranet.php";
if (!((isset($_SESSION['MM_Username'])) && (isAuthorized("",$MM_authorizedUsers, $_SESSION['MM_Username'], $_SESSION['MM_UserGroup'])))) {
 $MM_qsChar = "?";
 $MM_referrer = $_SERVER['PHP_SELF'];
 if (strpos($MM_restrictGoTo, "?")) $MM_qsChar = "&";
 if (isset($QUERY_STRING) && strlen($QUERY_STRING) > 0)
 $MM_referrer .= "?" . $QUERY_STRING;
 $MM_restrictGoTo = $MM_restrictGoTo. $MM_qsChar . "accesscheck=" . urlencode($MM_referrer);
 header("Location: ". $MM_restrictGoTo);
 exit;
}
?>
<?php
if (!function_exists("GetSQLValueString")) {
function GetSQLValueString($theValue, $theType, $theDefinedValue = "", $theNotDefinedValue = "")

{

 $theValue = get_magic_quotes_gpc() ? stripslashes($theValue) : $theValue;

 $theValue = function_exists("mysql_real_escape_string") ? mysql_real_escape_string($theValue) : mysql_escape_string($theValue);

 switch ($theType) {
	case "text":
 $theValue = ($theValue != "") ? "'" . $theValue . "'" : "NULL";
 break;
	case "long":
	case "int":
 $theValue = ($theValue != "") ? intval($theValue) : "NULL";
 break;
	case "double":
 $theValue = ($theValue != "") ? "'" . doubleval($theValue) . "'" : "NULL";
 break;
	case "date":
 $theValue = ($theValue != "") ? "'" . $theValue . "'" : "NULL";
 break;
	case "defined":
 $theValue = ($theValue != "") ? $theDefinedValue : $theNotDefinedValue;
 break;
 }
 return $theValue;
}
}

$editFormAction = $_SERVER['PHP_SELF'];
if (isset($_SERVER['QUERY_STRING'])) {
 $editFormAction .= "?" . htmlentities($_SERVER['QUERY_STRING']);
}

if ((isset($_POST["MM_insert"])) && ($_POST["MM_insert"] == "form")) {
 $insertSQL = sprintf("INSERT INTO licitacoes (tit_lic, dat_lic, num_lic, hor_lic, obj_lic, sit_lic, res_lic, tel_lic, ema_lic, sta_lic, dat_pub_lic, dat_abe_lic, dat_fec_lic, val_est, val_lic, ven_lic, hor_abe_lic) VALUES (%s, %s, %s, %s, %s, %s, %s, %s, %s, %s, %s, %s, %s, %s, %s, %s, %s)",
 GetSQLValueString($_POST['tit_lic'], "text"),
 GetSQLValueString($_POST['Dat_lic'], "date"),
 GetSQLValueString($_POST['num_lic'], "text"),
 GetSQLValueString($_POST['hor_lic'], "date"),
 GetSQLValueString($_POST['obj_lic'], "text"),
 GetSQLValueString($_POST['sit_lic'], "text"),
 GetSQLValueString($_POST['res_lic'], "text"),
 GetSQLValueString($_POST['tel_lic'], "text"),
 GetSQLValueString($_POST['ema_lic'], "text"),
 GetSQLValueString($_POST['sta_lic'], "text"),
 GetSQLValueString($_POST['dat_pub_lic'], "date"),
 GetSQLValueString($_POST['dat_abe_lic'], "date"),
 GetSQLValueString($_POST['dat_fec_lic'], "date"),
 GetSQLValueString($_POST['val_est'], "text"),
 GetSQLValueString($_POST['val_lic'], "text"),
 GetSQLValueString($_POST['ven_lic'], "text"),
 GetSQLValueString($_POST['hor_abe_lic'], "date"));

 mysql_select_db($database_cigas, $cigas);
 $Result1 = mysql_query($insertSQL, $cigas) or die(mysql_error());

 $insertGoTo = "cad_lic.php";
 if (isset($_SERVER['QUERY_STRING'])) {
	$insertGoTo .= (strpos($insertGoTo, '?')) ? "&" : "?";
	$insertGoTo .= $_SERVER['QUERY_STRING'];
 }
 header(sprintf("Location: %s", $insertGoTo));
}

$data = date("y-m-d");
$hora = date("H:i:s");
?>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<html xmlns="[http://www.w3.org/1999/xhtml">](http://www.w3.org/1999/xhtml)
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>Companhia de Gás do Amazonas - Cigás</title>
<style type="text/css">

<!--
a:link {

	color: #000066;
	text-decoration: none;
}

a:visited {

	color: #000066;
	text-decoration: none;
}

a:hover {

	color: #000066;
	text-decoration: underline;
}

a:active {

	color: #000066;
	text-decoration: none;
}

body,td,th {

	color: #666666;
}

.style40 {color: #FFFFFF; font-weight: bold; font-family: Verdana, Arial, Helvetica, sans-serif; font-size: 11px; }
.style41 {color: #000000}
body {

	background-image: url();
	background-color: #FFFFFF;
}
.style45 {
	font-family: Arial, Helvetica, sans-serif;
	color: #000066;
	font-weight: bold;
	font-size: 17px;
}
.style46 {
	font-family: Verdana, Arial, Helvetica, sans-serif;
	font-size: 11px;
}

.style47 {color: #000066}
-->

</style>
<script type="text/JavaScript">

<!--

function MM_swapImgRestore() { //v3.0
 var i,x,a=document.MM_sr; for(i=0;a&&i<a.length&&(x=a[i])&&x.oSrc;i++) x.src=x.oSrc;
}

function MM_preloadImages() { //v3.0
 var d=document; if(d.images){ if(!d.MM_p) d.MM_p=new Array();
	var i,j=d.MM_p.length,a=MM_preloadImages.arguments; for(i=0; i<a.length; i++)
	if (a[i].indexOf("#")!=0){ d.MM_p[j]=new Image; d.MM_p[j++].src=a[i];}}
}

function MM_findObj(n, d) { //v4.01
 var p,i,x; if(!d) d=document; if((p=n.indexOf("?"))>0&&parent.frames.length) {
	d=parent.frames[n.substring(p+1)].document; n=n.substring(0,p);}
 if(!(x=d[n])&&d.all) x=d.all[n]; for (i=0;!x&&i<d.forms.length;i++) x=d.forms[i][n];
 for(i=0;!x&&d.layers&&i<d.layers.length;i++) x=MM_findObj(n,d.layers[i].document);
 if(!x && d.getElementById) x=d.getElementById(n); return x;
}

function MM_swapImage() { //v3.0
 var i,j=0,x,a=MM_swapImage.arguments; document.MM_sr=new Array; for(i=0;i<(a.length-2);i+=3)
 if ((x=MM_findObj(a[i]))!=null){document.MM_sr[j++]=x; if(!x.oSrc) x.oSrc=x.src; x.src=a[i+2];}
}

//-->

</script>
</head>

<body onload="MM_preloadImages('imagens/Fig_Email2.gif')">
<table width="100%" border="0" align="center" cellpadding="0" cellspacing="0" id="missao">
 <tr>
	<td><div align="center">
	<label></label>

	<div align="left"><span class="style45">Cadastro de Licitação </span></div>
	<div align="center"></div></td>
 </tr>
</table>
<form action="<?php echo $editFormAction; ?>" method="POST" enctype="multipart/form-data" name="form" id="form">
 <table width="100%" border="1" align="center" cellpadding="0" cellspacing="2" bordercolor="#FFFFFF" bgcolor="#FFFFFF">
	<tr bordercolor="#000000" bgcolor="#DBDBDB">
 <td width="25%" height="25" bgcolor="#DBDBDB"><div align="center" class="style40 style47">
 <div align="left"> Titulo:</div>
 </div></td>
 <td width="75%" height="25" bgcolor="#FFFFFF"><input name="tit_lic" type="text" id="tit_lic" size="50" maxlength="50" />
 <input name="Dat_lic" type="hidden" id="Dat_lic2" value="<?php echo $data; ?>" />
 <input name="hor_lic" type="hidden" id="hor_lic2" value="<?php echo $hora; ?>" /></td>
	</tr>
	<tr bordercolor="#000000" bgcolor="#DBDBDB">
 <td width="25%" height="11" bgcolor="#DBDBDB"><div align="center" class="style40 style47">
 <div align="left"> Número:</div>
 </div></td>
 <td width="75%" height="11" bgcolor="#FFFFFF"><input name="num_lic" type="text" id="num_lic" size="50" maxlength="10" />
 </td>
	</tr>
	<tr bordercolor="#000000" bgcolor="#DBDBDB">
 <td width="25%" height="12" bgcolor="#DBDBDB"><div align="center" class="style40 style47">
 <div align="left"> Data da Publicação:</div>
 </div></td>
 <td height="12" bgcolor="#FFFFFF"><input name="dat_pub_lic" type="text" id="dat_pub_lic" size="50" maxlength="10" /></td>
	</tr>
	<tr bordercolor="#000000" bgcolor="#DBDBDB">
 <td height="25" bgcolor="#DBDBDB"><div align="center" class="style40 style47">
 <div align="left"> Data Abertura:</div>
 </div></td>
 <td width="75%" height="25" bgcolor="#FFFFFF"><input name="dat_abe_lic" type="text" id="dat_abe_lic" size="50" maxlength="50" /></td>
	</tr>
	<tr bordercolor="#000000" bgcolor="#DBDBDB">
 <td height="25" bgcolor="#DBDBDB"><div align="center" class="style40 style47">
 <div align="left">  Hora Abertura:</div>
 </div></td>
 <td width="75%" height="25" bgcolor="#FFFFFF"><input name="hor_abe_lic" type="text" id="hor_abe_lic" size="50" maxlength="50" /></td>
	</tr>
	<tr bordercolor="#000000" bgcolor="#DBDBDB">
 <td width="25%" height="25" bgcolor="#DBDBDB"><div align="center" class="style40 style47">
 <div align="left"> Objeto:</div>
 </div></td>
 <td width="75%" height="25" bgcolor="#FFFFFF"><label>
 <textarea name="obj_lic" cols="50" rows="5" id="obj_lic"></textarea>
 </label></td>
	</tr>
	<tr bordercolor="#000000" bgcolor="#DBDBDB">
 <td height="25" bgcolor="#DBDBDB"><div align="center" class="style40 style47">
 <div align="left"> Valor Estimado:</div>
 </div></td>
 <td height="25" bgcolor="#FFFFFF"><input name="val_est" type="text" id="val_est" size="50" maxlength="25" /></td>
	</tr>
	<tr bordercolor="#000000" bgcolor="#DBDBDB">
 <td height="25" bgcolor="#DBDBDB"><div align="center" class="style40 style47">
 <div align="left"> Responsável:</div>
 </div></td>
 <td width="75%" height="25" bgcolor="#FFFFFF"><input name="res_lic" type="text" id="res_lic" size="50" maxlength="25" /></td>
	</tr>
	<tr bordercolor="#000000" bgcolor="#DBDBDB">
 <td height="25" bgcolor="#DBDBDB"><div align="center" class="style40 style47">
 <div align="left"> Telefone:</div>
 </div></td>
 <td width="75%" height="25" bgcolor="#FFFFFF"><input name="tel_lic" type="text" id="tel_lic" size="50" maxlength="25" /></td>
	</tr>
	<tr bordercolor="#000000" bgcolor="#DBDBDB">
 <td height="25" bgcolor="#DBDBDB"><div align="center" class="style40 style47">
 <div align="left"> E-mail:</div>
 </div></td>
 <td width="75%" height="25" bgcolor="#FFFFFF"><input name="ema_lic" type="text" id="ema_lic" size="50" maxlength="25" /></td>
	</tr>
	<tr bordercolor="#000000" bgcolor="#DBDBDB">
 <td height="25" bgcolor="#DBDBDB"><div align="center" class="style40 style47">
 <div align="left"> Situação</div>
 </div></td>
 <td height="25" bgcolor="#FFFFFF"><textarea name="sit_lic" cols="50" rows="5" id="sit_lic"></textarea></td>
	</tr>
	<tr bordercolor="#000000" bgcolor="#DBDBDB">
 <td height="25" bgcolor="#DBDBDB"><div align="center" class="style40 style47">
 <div align="left"> Data de Fechamento:</div>
 </div></td>
 <td height="25" bgcolor="#FFFFFF"><input name="dat_fec_lic" type="text" id="dat_fec_lic" size="50" maxlength="50" /></td>
	</tr>
	<tr bordercolor="#000000" bgcolor="#DBDBDB">
 <td height="25" bgcolor="#DBDBDB"><div align="center" class="style40 style47">
 <div align="left"> Vencedor:</div>
 </div></td>
 <td height="25" bgcolor="#FFFFFF"><input name="ven_lic" type="text" id="ven_lic" size="50" maxlength="25" /></td>
	</tr>
	<tr bordercolor="#000000" bgcolor="#DBDBDB">
 <td height="25" bgcolor="#DBDBDB"><div align="center" class="style40 style47">
 <div align="left"> Valor da Licitação:</div>
 </div></td>
 <td height="25" bgcolor="#FFFFFF"><input name="val_lic" type="text" id="val_lic" size="50" maxlength="25" /></td>
	</tr>
	<tr bordercolor="#000000" bgcolor="#DBDBDB">
 <td height="25" bgcolor="#DBDBDB"><div align="center" class="style40 style47">
 <div align="left"> Status:</div>
 </div></td>
 <td height="25" bgcolor="#FFFFFF"><select name="sta_lic" id="sta_lic">
 <option value="Inativo">Selecione um</option>
 <option value="Novas">Novas</option>
 <option value="Andamento">Andamento</option>
 <option value="Encerradas">Encerradas</option>
 </select></td>
	</tr>
	<tr bordercolor="#000000" bgcolor="#DBDBDB">
 <td height="25" bgcolor="#DBDBDB"><div align="center" class="style40 style41">
 <div align="left"> <span class="style47">Arquivo:</span></div>
 </div></td>
 <td height="25" bgcolor="#FFFFFF"><label>
 <input name="arq_lic" type="file" id="arq_lic" />
 </label></td>
	</tr>
 </table>
 <input type="hidden" name="MM_insert" value="form1">
<input type="hidden" name="MM_insert" value="form" />
</form>
<table width="100%" border="1" align="center" cellpadding="0" cellspacing="2" bordercolor="#FFFFFF" bgcolor="#FFFFFF">
 <tr bordercolor="#000000" bgcolor="#DBDBDB">
	<td width="50%" height="25" bordercolor="#FFFFFF" bgcolor="#FFFFFF"><label></label></td>
	<td width="20%" height="25" bordercolor="#FFFFFF" bgcolor="#FFFFFF"> </td>
	<td width="10%" bordercolor="#FFFFFF" bgcolor="#FFFFFF"> </td>
	<td width="10%" bordercolor="#000000" bgcolor="#FFFFFF"><div align="center" class="style46"><a href="java script:document.form.submit()">Salvar</a></div>
 <a href="cont_index.php"></a></td>
	<td width="10%" bgcolor="#FFFFFF"><div align="center" class="style46"><a href="cont_lic.php">Voltar</a></div></td>
 </tr>
</table>
<p> </p>
</body>
</html>