These are my codes And i'm getting error 

> 
> Notice: Undefined index: command in E:\xampp\htdocs\Shop\_cart\products.php on line 17
> 
> 
> 

Javascript:

```
<script language="javascript">
function addtocart(pid){
document.form1.productid.value=pid;
document.form1.command.value='add';
document.form1.submit();
}
</script>  

```

HTML Code:

```
<form name="form1" action="">
<input type="hidden" name="productid" />
<input type="hidden" name="command" />
<input type="button" value="Add to Cart" onclick="addtocart(1)" />
</form>  

```

PHP Code:

```
if($_REQUEST['command']=='add' && $_REQUEST['productid']>0){
$pid=$_REQUEST['productid'];
addtocart($pid,1);
header("location:shoppingcart.php");
exit();

```