keydown event new value

Question

Browser: Google Chrome V19.0.1084.52 I have a textbox which needs to be a number less than or equal to 255, on keydown I want to check if this value is above or equal to 255 else prevent the event. In the Console when I console.log the event it will show event.srcElement.value as the value will appear i.e. from 12 => 123, when I console.log just event.srcElement.value it will show as the input was, not will be. Console.log's are happening one after the other, nothing in between, no pauses. How can I find what the new value of a textbox will be on keydown and why is the console.log returning different results? Here's my code: ``` function inputNumeric(event,max) { console.log (event); console.log ('event.originalEvent.srcElement.value: '+event.originalEvent.srcElement.value); console.log ('event.srcElement.value: '+event.srcElement.value); } $("#rs485addr").keydown(function(event) { inputNumeric(event); }); ``` Console.log: ``` event.originalEvent.srcElement.value: 12 event.srcElement.…

Accepted Answer

I'm not sure if it could be of any help, but when I had to deal with a similar situation in an event listener I used a `setTimeout()` with 1ms timeout where I put the main functionality checking for the value, etc.

That is because when the `keydown` event is fired the input field is not yet populated with the new data.

Simple jQuery example:

```
$('#input').on('keydown', function(e) {
  var field = $(this);
  var prevValue = field.val();
  setTimeout(function() {
    // check if new value is more or equal to 255
    if (field.val() >= 255) {
      // fill with previous value
      field.val(prevValue);
    }

}, 1);
});
```

UPDATE

Use 'input' event in modern browsers.

```
var prevValue = 0;
$('#input').on('input', function(e) {
  var field = $(this);
  // check if new value is more or equal to 255
  if (field.val() >= 255) {
    // fill with previous value
    field.val(prevValue);
  } else {
    // If value is lower than 255 set it in prev value.
    prevValue = field.val();
  }
});
```

keydown event new value

Solution

Problem