Update quantity echo ahref - php

Question

I'm trying to create an integer update form field for my cart system. On the page, I already have a + and - function to increase and decrease the quantity by 1. How could I include an integer form field next to the (+) and (-) to udpate by a certain result and then send this to the cart page. Thank you very much for any help.
This is the main part of the code that is enclosed within PHP (I left out the information before the first a href link because it isn't important)
(+)
(-)

Answer 1

I'm not quite sure if i really get your question right, but i think you want to change an input field in a chart.
i think you should solve that problem with JavaScript instead of PHP, because you have to reload the page on every Click.
in jQuery it would like that:
$(".increase").each(function() {
$(this).click(function() {
var ipt = $("#" + $(this).attr("data-what"));
ipt.val(parseInt(ipt.val()) + 1);
});
});
$(".decrease").each(function() {
$(this).click(function() {
var ipt = $("#" + $(this).attr("data-what"));
ipt.val(parseInt(ipt.val()) - 1);
if(parseInt(ipt.val()) < 0) {
ipt.val(0);
}
});
});
and the html is:
<div class="item">Item 1 <input type="text" id="item1" value="1" size="2"> (+1 | -1)</div>
<div class="item">Item 2 <input type="text" id="item2" value="1" size="2"> (+1 | -1)</div>
<div class="item">Item 3 <input type="text" id="item3" value="1" size="2"> (+1 | -1)</div>
see http://jsfiddle.net/axYfq/4/
and with the submit button you get the right quantity :)

Answer 2

You'll have to post a form to cart.php:
<form action="cart.php" method="post">
<input type="text" name="qty"/>
<input type="submit" name="submit_increase" value="(+)"/>
</form>
<form action="cart.php" method="post">
<input type="text" name="qty"/>
<input type="submit" name="submit_remove" value="(-)"/>
</form>
And in your cart.php, you can use if (isset($_POST['submit_increase'])) to determine if you're increasing or decreasing, then $_POST['qty'] to grab the number of items to add/remove.
This isn't the only solution. You could use one form, hidden inputs, or javascript to build a query string. Its up to you.

Answer 3

You could use javascript getelementbyID to do this.
First, you will need a form field with an appropriate ID:
<input type="text" name="quantity" id="NumberOfItems" />
Then put a span around the (+) and (-) to call a JS function:
<span onclick="IncrementNumber()">(+)</span>
<span onclick="DecrementNumber()">(-)</span>
Then you can use getelementbyID to change the value when they click a button:
function IncrementNumber()
{
document.getElementById("NumberOfItems").value-=-1; // Messy, but works
}
function DecrementNumber()
{
document.getElementById("NumberOfItems").value-=1;
}

Answer 4

I believe you need to use a form here. Try doing:
<form action="#" method="POST">
<input type="hidden" name="user_action" value="increase">
<input type="submit" value="increase">
</form>
<form action="#" method="POST">
<input type="hidden" name="user_action" value="decrease">
<input type="submit" value="decrease">
</form>
This way you will output two buttons, and when the user clicks on each one, you will get their action from the $_POST variable. So then you could do something like:
<?php
if(isset($_POST['increase'])){
$number_of_items += 1;
}
if(isset($_POST['decrease'])){
$number_of_items -= 1;
}
?>
<p>You have ordered <?php echo $number_of_items; ?> items</p>