Detect changed input text box

问题:

I've looked at numerous other questions and found very simple answers, including the code below. I simply want to detect when someone changes the content of a text box but for some reason it's not working... I get no console errors. When I set a breakpoint in the browser at the change() function it never hits it.

$('#inputDatabaseName').change(function () { 
    alert('test'); 
});

<input id="inputDatabaseName">

回答1:

You can use oninput event like in jQuery like this:

$('#inputDatabaseName').on('input',function(e){
    alert('Changed!')
});

In pure JavaScript

document.querySelector("input").addEventListener("change",function () {
  alert("Input Changed");
})

Or like this:

<input id="inputDatabaseName" onchange="youFunction();"
onkeyup="this.onchange();" onpaste="this.onchange();" oninput="this.onchange();"/>

回答2:

try keyup instead of change.

<script type="text/javascript">
   $(document).ready(function () {
       $('#inputDatabaseName').keyup(function () { alert('test'); });
   });
</script>

Here's the official jQuery documentation for .keyup().

回答3:

Each answer is missing some points, so here is my solution:

$("#input").on("input", function(e) {
  var input = $(this);
  var val = input.val();

  if (input.data("lastval") != val) {
    input.data("lastval", val);

    //your change action goes here 
    console.log(val);
  }

});

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<input type="text" id="input">
<p>Try to drag the letters and copy paste</p>

The Input Event fires on Keyboard input, Mouse Drag, Autofill and Copy-Paste tested on Chrome and Firefox. Checking for previous value makes it detect real changes, which means not firing when pasting the same thing or typing the same character or etc.

Working example: http://jsfiddle.net/g6pcp/473/

---

update:

And if you like to run your change function only when user finishes typing and prevent firing the change action several times, you could try this:

var timerid;
$("#input").on("input", function(e) {
  var value = $(this).val();
  if ($(this).data("lastval") != value) {

    $(this).data("lastval", value);
    clearTimeout(timerid);

    timerid = setTimeout(function() {
      //your change action goes here 
      console.log(value);
    }, 500);
  };
});

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<input type="text" id="input">

If user starts typing (e.g. "foobar") this code prevents your change action to run for every letter user types and and only runs when user stops typing, This is good specially for when you send the input to the server (e.g. search inputs), that way server does only one search for foobar and not six searches for f and then fo and then foo and foob and so on.

回答4:

Text inputs do not fire the change event until they lose focus. Click outside of the input and the alert will show.

If the callback should fire before the text input loses focus, use the .keyup() event.

回答5:

onkeyup, onpaste, onchange, oninput seems to be failing when the browser performs autofill on the textboxes. To handle such a case include "autocomplete='off'" in your textfield to prevent browser from autofilling the textbox,

Eg,

<input id="inputDatabaseName" autocomplete='off' onchange="check();"
 onkeyup="this.onchange();" onpaste="this.onchange();" oninput="this.onchange();" />

<script>
     function check(){
          alert("Input box changed");
          // Things to do when the textbox changes
     }
</script>

回答6:

In my case, I had a textbox that was attached to a datepicker. The only solution that worked for me was to handle it inside the onSelect event of the datepicker.

<input type="text"  id="bookdate">

$("#bookdate").datepicker({            
     onSelect: function (selected) {
         //handle change event here
     }
});

回答7:

I think you can use keydown too:

$('#fieldID').on('keydown', function (e) {
  //console.log(e.which);
  if (e.which === 8) {
    //do something when pressing delete
    return true;
  } else {
    //do something else
    return false;
  }
});

回答8:

WORKING:

$("#ContentPlaceHolder1_txtNombre").keyup(function () {
    var txt = $(this).val();
        $('.column').each(function () {
            $(this).show();
            if ($(this).text().toUpperCase().indexOf(txt.toUpperCase()) == -1) {
                $(this).hide();
            }
        });
    //}
});