JavaScript Form Validate rows in HTML table - php

Question

For some reasons my javascript form validation does not go through every row in the table.
I created the table with the codes below:
The $usr variable is just a result of another process:
<form name="myForm" action="addAccessories.php" method="post" onsubmit="return validateForm(this);">
<table border="1" id="IT">
<tr>
<th>Barcode<em>*</em></th>
<th>Current stock</th>
</tr>
<?php
for($id=1; $id<=$usr; $id++){
?>
<tr>
<td><input type="hidden" name="id[]" value="<?php echo $id; ?>" />
<input type="text" name="bar_code<?php echo $id; ?>" id="bar_code<?php echo $id; ?>" value="" /></td>
<td><input type="text" name="num_stock<?php echo $id; ?>" value="0" id="num_stock<?php echo $id; ?>"/></td>
<?php
}
?>
<tr>
<td> </td>
<td> <button data-theme="b" input type="submit" name="Submit" value="Submit">Add accessories</button></td>
</tr>
</table>
</form>
The number of rows from this table is: rows = $usr + 1
My validation form codes:
<script type="text/javascript">
function validateForm(){
var errors = [];
for(i = 1; i < document.getElementById("IT").rows.length; i++){
var barcode = document.getElementById('bar_code'+i).value;
var des = document.getElementById('description'+i).value;
var num_stock = document.getElementById('num_stock'+i).value;
if(barcode == null || barcode == ""){
errors[errors.length] = "You must enter barcode.";
}
if(isNaN(num_stock)){
errors[errors.length] = "Current stock must be an integer";
}
if(num_stock < 0){
errors[errors.length] = "Current stock must be a positive number";
}
if (errors.length > 0) {
reportErrors(errors);
return false;
}
return true;
}
}
function reportErrors(errors){
var msg = "There were some problems...\n";
for (var i = 0; i<errors.length; i++) {
var numError = i + 1;
msg += "\n" + numError + ". " + errors[i];
}
alert(msg);
}
</script>
This process only validates the 1st row in the table then stop. Can anyone show me what went wrong and how to fix it?
Thank you very much for your help

Answer 1

Your code is making life way more complex than it needs to be. A simpler approach is to just deal with the form controls, e.g. since you are already passing a reference to the form from the submit listener:
function validateForm(form) {
var errors = [];
var c, cs = form.elements;
var reB = /^bar_code/;
var reN = /^num_stock/;
var reD = /^[0-9]+$/;
for (var i=0, iLen=cs.length; i<iLen; i++) {
c = cs[i];
if (reB.test(c.name) && c.value == '') {
errors.push('You must enter barcode.'];
} else if (reN.test(c.name) && !reD.test(c.value)) {
errors.push('Stock number must be a positive integer.'];
}
}
// deal with errors...
}
Note that in the test:
> barcode == null || barcode == ""
barcode is a string, so the first test will never return true and the second is sufficient if you want to see if it's empty.