JQuery: detect change in input field [duplicate]

Question

I want to detect when a user's keyboard actions alter the value of a text field. It should work consistently across modern browsers.

The JQuery page for the .keypress event says it's not consistent? Also, it doesn't work for backspace, delete etc.

I can't use .keydown as it is because it reacts to shift, alt and arrow keys etc. Also, it doesn't fire more than once when the user holds down a key and multiple characters are inserted.

Is there a concise method I'm missing? Or should I use .keydown and filter out events that are triggered by arrow keys, shift and so on? My main concern is there will be keys that I'm not aware should be filtered. (I nearly forgot about alt and ctrl, I suppose there could be others) But then how would I detect the key being held down and inserting multiple characters?

As a bonus it would detect changes due to pasting (including right-clicking) but I have the solution to that from here.

Answer 1

You can bind the 'input' event to the textbox. This would fire every time the input changes, so when you paste something (even with right click), delete and type anything.

$('#myTextbox').on('input', function() {
    // do something
});

If you use the change handler, this will only fire after the user deselects the input box, which may not be what you want.

There is an example of both here: http://jsfiddle.net/6bSX6/

Answer 2

Use jquery change event

Description: Bind an event handler to the "change" JavaScript event, or trigger that event on an element.

An example

$("input[type='text']").change( function() {
  // your code
});

The advantage that .change has over .keypress , .focus , .blur is that .change event will fire only when input has changed

Answer 3

Same functionality i recently achieved using below function.

I wanted to enable SAVE button on edit.

1. Change event is NOT advisable as it will ONLY be fired if after editing, mouse is clicked somewhere else on the page before clicking SAVE button.
2. Key Press doesnt handle Backspace, Delete and Paste options.
3. Key Up handles everything including tab, Shift key.

Hence i wrote below function combining keypress, keyup (for backspace, delete) and paste event for text fields.

Hope it helps you.

function checkAnyFormFieldEdited() {
    /*
     * If any field is edited,then only it will enable Save button
     */
    $(':text').keypress(function(e) { // text written
        enableSaveBtn();
    });

    $(':text').keyup(function(e) {
        if (e.keyCode == 8 || e.keyCode == 46) { //backspace and delete key
            enableSaveBtn();
        } else { // rest ignore
            e.preventDefault();
        }
    });
    $(':text').bind('paste', function(e) { // text pasted
        enableSaveBtn();
    });

    $('select').change(function(e) { // select element changed
        enableSaveBtn();
    });

    $(':radio').change(function(e) { // radio changed
        enableSaveBtn();
    });

    $(':password').keypress(function(e) { // password written
        enableSaveBtn();
    });
    $(':password').bind('paste', function(e) { // password pasted
        enableSaveBtn();
    });


}