Thank you for the replies. As the consensus is that this is not possible I did a work-around that I am posting here:
The basic principle is to blur the input field and then capture the keypresses to add them to the input field anyway.
In this situation I am using a barcode scanner with all-numeric barcodes so that's what this will work with but if someone else should be interested it should be trivial to adapt to other situations:
<html>
<head>
<script src="http://code.jquery.com/jquery-1.11.1.min.js"></script>
<script>
$( document ).ready( function () {
// _input_fields and _scan_fields are jQuery objects with the relevant elements
let _input_fields = $("input[type=number], input[type=text], input:not([type]), select");
let _scan_fields = $("input[type=number].scanner");
// _ignore is set to true when a scannable field actually _should_ get focus
var _ignore = false;
// onfocus() for relevant input fields on page
_input_fields.focus(function(){
// only do something if scannable fields shouldn't actually get focus
if (!_ignore) {
// outer is the current input field that is getting focus
let outer = this;
// found is set to true if the current input field is scannable
let found = false;
// loop through all scannable fields to see if the current input field is one of them
_scan_fields.each(function(index) {
// inner is one of the scannable fields, possibly the current input field
let inner = this;
// _field stores the current input field _if_ it is scannable
var _field;
// only check (and potentially reset key capture) if we have not found the current
// input field to be one of the scannable fields (yet)
if (!found) {
// check if the current input field "outer" is the currently examined
// scannable field "inner"
if (inner == outer) {
// the current input field is one of the scannable fields
// immediately remove focus to disable mobile keyboard
inner.blur();
// remember which input field we have found and disable further checks
_field = inner;
found = true;
// remove any existing keycapture (might destroy existing functionality!!!)
$(document).off("keypress");
// capture keypresses and add numbers to the input field
$(document).keypress(function(event){
var _field = inner;
let keynum = event.which;
if (keynum == 13) { // enter
// ignore or submit?
} else if ((keynum < 48) || (keynum > 57)) {
// not-a-number, ignore in this case
} else {
// a number, add to field value
$(_field).val($(_field).val() + String.fromCharCode(event.which));
}
});
} else {
// this is a regular field
// remove any existing keycapture (might destroy existing functionality!!!)
$(document).off("keypress");
}
}
});
}
});
// add a button after each scannable input field
$("input[type=number].scanner").after(function(){
return "<button class='descanner'>123</button>";
});
// if those buttons are pressed, the input field before them actually gets focus
// overriding the new behaviour
$("button.descanner").click(function(event){
// these buttons do not submit the form
event.preventDefault();
// remove any existing keycapture (might destroy existing functionality!!!)
$(document).off("keypress");
// set focus for the input field but make sure we don't catch this above
// also, clear content of input field
_ignore = true;
$(this).prev("input[type=number].scanner").val("").focus();
_ignore = false;
});
});
</script>
</head>
<body>
<form>
<input type="number" name="field1" class="" />
<input type="text" name="field2" class="" />
<input name="field3" class="" />
<select name="field4" class="">
<option value="bac">abc</option>
</select>
<input type="number" name="field5" class="scanner" />
<input type="number" name="field6" class="" />
<input type="number" name="field7" class="scanner" />
</form>
</body>
</html>
The form has 7 fields and 2 of those have the desired functionality. To enable manual edit of those fields a button is added next to each of those 2 fields.
This has been tested in Chrome 55 and on a Zebra TC 51 with Webview updated to Chromium 55.
blur. You can't tell the keyboard to show/hide, it's controlled by the browser.