match() function and match variables - php

Question

now i have a text-input and a php variables.
$price = 200;
<input type="text" name="promotion_code">
after users type in value of 'promotion_code' , without submit button , or any links.
it's can match 'promotion_code' between javascript on that pages.
lets say the javascript :
var str="123203";
so i want match the 'promotion_code' with 'var str' .
if match then $price = $price - 10;
if not match then $price value doesn't change ..
any could helps or any methods to solve this ?
note :!! to be told. this form did not have a submit button .. the compare process should be works in time when the user input the promotion_code

Answer 1

You should not do that with JavaScript, it is no secure enough.
Anyone can view your JavaScript code by looking at the source of your page.
Try to make it with an ajax request.
jQuery.ajax({
type : "post",
url : "request.php",
data : "code=" +jQuery("input[name=promotion_code]").val(),
success : function(ret){
jQuery("#price").text(ret);
}
});
Here you call the page request.php with the value code
Here what can be request.php :
$price = 200;
$code = $_POST["code"];
if( $code == "123203" ){
$price -= 10;
}
return $price;
Then you update the price field with the data returned by the request.php page.
You have to adapt that code of course.
I hope this can help.

Answer 2

Make sure to do that on the server since anyone can see the code in the source of the page. Also $price is on the server and the client value is not available to the server until you send a request back to the server using for example AJAX
So something like
<form action="purchase.php" id="form1">
Promotion code: <input type="text" name="promotion_code" id="prCode" />
<input type="button" id="prCodeBut" value="Apply" />
Price: <input type="text" readonly="readonly"
name="finalprice" id="fPrice" value="<?PHP echo $price; ?>" />
</form>
JavaScript
DEMO 1 - using click
var orgPrice = <?PHP echo $price; ?>;
window.onload=function() {
document.getElementById("prCodeBut").onclick=function(){
// hardcoding the promocode is NOT recommended
if (document.getElementById("prCode").value == "<?php echo $promocode; ?>") {
document.getElementById("fPrice").value=orgPrice-10;
}
}
}
DEMO 2 using onkeyup
var orgPrice = <?PHP echo $price; ?>;
window.onload=function() {
document.getElementById("prCode").onkeyup=function(){
// hardcoding the promocode is NOT recommended
if (document.getElementById("prCode").value == "<?php echo $promocode; ?>") {
document.getElementById("fPrice").value=orgPrice-10;
}
}
}
DEMO 3 using onblur
var orgPrice = <?PHP echo $price; ?>;
window.onload=function() {
document.getElementById("prCode").onblur=function(){
// hardcoding the promocode is NOT recommended
if (document.getElementById("prCode").value == "<?php echo $promocode; ?>") {
document.getElementById("fPrice").value=orgPrice-10;
}
}
}
Ajax to hide the promocode
// delay from http://stackoverflow.com/a/1909508/295783
var delay = (function(){
var timer = 0;
return function(callback, ms){
clearTimeout (timer);
timer = setTimeout(callback, ms);
};
})();
$(function() {
$("#prCodeBut").on("keyup",function() {
delay(function() {
$.get("checkPromo.php",{promotion: $("#prCode").val()},function(data) {
$("#fPrice").val(data);
});
},300);
});
});