How do i automatically hit a submit button in jquery - php

Question

i have a ScanField. In this field i'm scanning a barcode. After that i'm cutting the last four character of the bardcode-string and give it to the hiddenField. And from that hidden field when i click on the search button i pass it to the php site via ajax.
for example: i'm scanning a barcode: TWRG000000009102 in the hiddenfield shows 9102 and after that im passing the value to ajax.
Everthing works fine but i would like to do it automatically. When the hidden inputField was filled it should fire an event and pass the value to ajax.
my code:
<label for="myType">
<select id="myType" name="myType" size="5">
<option value="01">B&C</option>
<option value="02">James Nicholson</option>
<option value="F.O.L">Fruit Of The Loom</option>
<option value="TeeJays">TeeJays</option>
</select>
</label>
<br>
<label for="hiddenField">hiddenField:</label>
<input type="text" name="hiddenField" style="width:300px"><br>
<label for="myScan">Scanfield:</label>
<input type="text" name="myScan" style="width:300px" autofocus>
<button type="submit">Search</button>
<div id="result"></div>
<script>
$(document).ready(function(){
$('input[name=myScan]').on('keypress', function(e){
if(e.which == 13) {
var scanField = $(this).val();
console.log(scanField);
var lastFour = scanField.substr(scanField.length - 4);
$('input[name=hiddenField]').val(lastFour);
}
});
$('button').on('click', function(){
var postForm = {
'myType' : $('#myType').val(),
'myScan' : $('input[name=hiddenField]').val()
};
$.ajax({
url: "index.php",
type: "POST",
data: postForm,
dataType: "text",
success: function(data){
$('#result').html(data);
}
});
});
});
here the html example: https://jsfiddle.net/froouf9f/

Answer 1

Once you save value to hidden field, you can trigger button click event using:
$("button").trigger("click");
Try this:
$('input[name=myScan]').on('keypress', function(e){
if(e.which == 13) {
var scanField = $(this).val();
console.log(scanField);
var lastFour = scanField.substr(scanField.length - 4);
$('input[name=hiddenField]').val(lastFour);
$("button").trigger("click");
}
});