False value being passed in POST method

1

I have an Ajax call that loops through a json file with the following code:

It calls a function in the form tag as follows:

When I try to validate the quantity to make sure that it’s a positive number less than ten, I use the following javascript:

function myFunction() {
var x;
x = document.getElementById(‘numb’).value;
alert(x);//this prints 0 every time
if ( isNaN(x) || (x < 0) || (x > 10)) {
alert(“Quantity must be a positive number less than 10.”);
event.preventDefault();
return false;
} else {
alert(“Input OK”);
}
}

The problem is that it doesn’t get the $_POST value of the textbox, it gets the value of zero like how the textbox is initialized every time.

2

A programming friend of mine pointed out that it’s iterating through a loop of ids and the id is the same for every text input so I changed it to:

and I changed my function to:

function myFunction() {
var x, i, y;

for (i = 1; i < 7; i++) {
y = ‘numb_’ + i;
x = document.getElementById(y).value;
//alert(y);
}
if ( isNaN(x) || (x < 0) || (x > 10)) {

alert("Quantity must be a positive number less than 10.");
event.preventDefault(); 
return false;

} else {
alert(“Input OK”);
}
}

alert(y); prints out numb_1 every time so it’s not looping properly. How can I improve my loop?

3

Hello and welcome!

The only problem I see is that You’re using the wrong type of quotes:

function myFunction() {
  var x, i, y;

  for (i = 1; i < 7; i++) {
    // Wrong:
    // y = ‘numb_’ + i;
    y = 'numb_' + i;
    x = document.getElementById(y).value;
    //alert(y);

    if (isNaN(x) || (x < 0) || (x > 10)) {

      alert("Quantity must be a positive number less than 10.");
      event.preventDefault();
      return false;

    } else {
      // Wrong
      // alert(“Input OK”);
      alert("Input OK");
    }
  }
}
4

With the help of a participant at another forum, I was able to find a solution. It looks like this:

function myFunction() {
var x, y;
var elements = document.querySelectorAll(’[id^=“numb_”]’);

for (var i = 1; i < elements.length; i++) {

y = elements[i].id;

x = document.getElementById(y).value;  

if ( isNaN(x) || (x < 1) || (x > 10)) {

alert("Quantity must be a positive number less than 10.");
event.preventDefault(); 
return false;

} else {
return true;
}
}
}