Get key from input id jQuery - php

Question

I have list with several inputs
<input type="hidden" id="elevens_id_ea" value="<?php echo $_GET['elev_id']; ?>" />
<input type="hidden" id="arskursen_ea" value="<?php echo $arskursen; ?>" />
<?php
if ($extraanpassning_hamta['atgard'] == true){
?>
<input name="extraanpassning" id="knapp[<?php echo $amnets_id['amne_id']; ?>]" type="button" class="btn-u rounded btn-u-red btn-sm" value="Ja">
<?php } else { ?>
<input name="extraanpassning" id="knapp[<?php echo $amnets_id['amne_id']; ?>]" type="button" class="btn-u rounded btn-u-green btn-sm" value="Nej">
<?php } ?>
The main problem is how to "catch" the value in the two latest inputs with:
id="knapp[<?php echo $amnets_id['amne_id']; ?>]"
If knapp[4] -> how do I get the 4?
The code above is a part of a button that changes value when the user presses it (without refreshing the page).
The JS
<script>
$(document).ready(function(){
$('input[type="button"]').click(function(){
var extraanpassningVal = $(this).attr("value");
var amne_id_ea = $(this).attr("id");
var elevens_id_ea = $("#elevens_id_ea").val(); //värdet av elev_id
var arskursen_ea = $("#arskursen_ea").val(); //värdet av elev_id
$.ajax({
type: "POST",
url: "iup_extraanpassning_byta.php",
data: {extraanpassningType: extraanpassningVal, amne_id_ea: amne_id_ea, elevens_id_ea: elevens_id_ea, arskursen_ea: arskursen_ea},
success: function() {
location.reload();
}
})
});
});
</script>
EDIT:
The main problem is how to get the key from a input with an id like knapp[4].
How do get the key within knapp[]?
Update (thanks to user:SpYk3HH)
<script>
$(document).ready(function(){
$('input[type="button"]').click(function(){
var key = this.id.replace(/knapp|\[|\]/g, ''), // <---They key
extraanpassningVal = $(this).attr("value"),
amne_id_ea = $(this).attr("id"),
elevens_id_ea = $("#elevens_id_ea").val(),
arskursen_ea = $("#arskursen_ea").val();
if (this.ajax) this.ajax.abort(); // helps prevent multiple ajaxing (multiclicking)
this.ajax = $.ajax({
type: "POST",
url: "iup_extraanpassning_byta.php",
data: {extraanpassningType: extraanpassningVal, amne_id_ea: amne_id_ea, elevens_id_ea: elevens_id_ea, arskursen_ea: arskursen_ea},
success: function() {
location.reload();
}
})
})
});
</script>

Answer 1

I think I get it? You want the key when calling the button in JS? So like say: key = this.id.replace(/knapp|\[|\]/g, '')
Update, I didn't see the brackets before
$('input[type="button"]').click(function(){
var key = this.id.replace(/knapp|\[|\]/g, ''), // <---They key
extraanpassningVal = $(this).attr("value"),
amne_id_ea = $(this).attr("id"),
elevens_id_ea = $("#elevens_id_ea").val(),
arskursen_ea = $("#arskursen_ea").val();
if (this.ajx) this.ajx.abort(); // helps prevent multiple ajaxing (multiclicking)
this.ajx = $.ajax({/* options */});
})
Does that help?
FYI, $(this).attr("id") and this.id are the same thing
$('[name=test]').each(function(i) { $('#bob').text(this.id.replace(/knapp|\[|\]/g, '')) })
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.9.1/jquery.min.js"></script>
<input id="knapp4" name="test" value='my id is "knapp[4]"' />
<hr />
key: <span id="bob"></span>

Answer 2

Try this.
var amne_id_ea = "knapp[4]",
value = amne_id_ea.substring(amne_id_ea.lastIndexOf("[")+1,amne_id_ea.lastIndexOf("]"));
alert(value);
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.8.3/jquery.min.js"></script>
Hope you are expecting this.