Aqui la respuesta.
<script>
patron=new Object();
patron.RazonSocial=/^([A-Za-z0-9 ]+)$/;
patron.Ruc=/^([1-2][0][0-9]{9})$/;
patron.Direccion=/^([A-Za-z0-9 ]+)$/;
patron.Telefono=/^(([2-7]{1}[0-9]{6}))$/;
patron.Email=/^[]([a-z]|[0-9]){3,14}@[a-z]{4,15}\.([com]|[net])/;
patron.SitioWeb=/^[w]{3}[.][a-z]{4,15}\.([com]|[net])/;
patron.RPM=/^([#]|[*]){9})$/;
M
function validar()
{
elementos=datos.elements;
for(i=0;i<elementos.length;i++)
{
v=elementos[i].validador;
if(!v) continue;
r=patron[v];
e=r.exec(elementos[i].value);
if(!e){
alert("Error en: " +v+" con el valor: "+elementos[i].value);
elementos[i].focus();
return false;
}
}
return true;
}
function back(){
location.href="../tables/providers.php";
return true;
}
</script>
<body>
<span class="titulosImportantes">Modulo para insertar nuevo Proveedor </span>
<hr />
<form id="datos" name="datos" method="post" action="" onSubmit="return validar();">
<table width="79%" border="0" align="center" cellpadding="3">
<tr>
<td width="142" height="34"><span class="Estilo4">Código</span></td>
<td width="24"><span class="Estilo2"></span></td>
<td width="515" colspan="3">
<label>
<input name="txtcodprov" type="text" id="txtcodprov" value='<? echo $cad; ?>' size="15" maxlength="4" readonly="true"/>
</label>
<span class="Estilo5">(*)</span></td>
</tr>
<tr>
<td><span class="Estilo4">Razón Social </span></td>
<td><span class="Estilo2"></span></td>
<td colspan="3"><input name="txtname" type="text" id="txtname" size="50" maxlength="150" validador="RazonSocial"/>
<span class="Estilo5">(*)</span></td>
</tr>
<tr>
<td><span class="Estilo4">Ruc</span></td>
<td><span class="Estilo2"></span></td>
<td colspan="3"><input name="txtruc" type="text" id="txtruc" size="20" maxlength="11" validador="Ruc"/></td>
</tr>
<tr>
<td><span class="Estilo4">Dirección</span></td>
<td><span class="Estilo2"></span></td>
<td colspan="3"><label>
<input name="txtdir" type="text" id="txtdir" size="50" maxlength="100" validador="Direccion"/>
</label> <span class="Estilo5">(*)</span></td>
</tr>
<tr>
<td><span class="Estilo4">Distrito</span></td>
<td><span class="Estilo2"></span></td>
<td colspan="3"><label>
<select name="cbodis" id="cbodis">
<?php
for($i=0;$distritos[$i];$i++){
echo("<option value='$distritos[$i]'>$distritos[$i]</option>");
}
?>
</select>
</label><span class="Estilo5">(*)</span></td>
</tr>
<tr>
<td><span class="Estilo4">Telefono</span></td>
<td><span class="Estilo2"></span></td>
<td colspan="3"><label>
<input name="txtfon" type="text" id="txtfon" size="30" maxlength="15" validador="Telefono"/>
</label> <span class="Estilo5">(*)</span></td>
</tr>
<tr>
<td><span class="Estilo4">Fax</span></td>
<td><span class="Estilo2"></span></td>
<td colspan="3"><label>
<input name="txtfax" type="text" id="txtfax" size="30" maxlength="15" />
</label> </td>
</tr>
<tr>
<td><span class="Estilo4">E - mail </span></td>
<td><span class="Estilo2"></span></td>
<td colspan="3"><label>
<input name="txtmail" type="text" id="txtmail" size="50" maxlength="100" validador="Email"/>
</label> </td>
</tr>
<tr>
<td><span class="Estilo4">Sitio Web </span></td>
<td><span class="Estilo2"></span></td>
<td colspan="3"><label>
<input name="txtweb" type="text" id="txtweb" size="50" maxlength="60" validador="SitioWeb"/>
</label> </td>
</tr>
<tr>
<td><span class="Estilo4">RPM </span></td>
<td><span class="Estilo2"></span></td>
<td colspan="3"><label>
<input name="txtrpm" type="text" id="txtrpm" size="7" maxlength="7" validador="RPM"/>
</label></td>
</tr>
<tr>
<td colspan="2"><label>
<div align="center">
<input name="btnGrabar" type="submit" id="btnGrabar" value="Grabar Proveedor" />
</div>
</label></td>
<td colspan="3">
<label><div align="center">
<input name="btnCancelar" type="button" id="btnCancelar" value="Cancelar" onclick="back()"/>
</div></label></td>
</tr>
</table>
</form>
<p> </p>
</body>
</html>