I want to check if user changes the value of a textbox. If the user changes the value, then I want to display the changed value in a different textbox.
jquery has an event for this, .change(), this event will detect content changes when the textbox looses focus.
If you are wanting to detect the change at every keypress, .keyup() and .keydown() might be better suited for your needs.
Examples for your intended use:
//just change '.change' to '.keyup' or '.keydown' the rest is the same.
$('input').change(function() {
$('target').val(this.value);
});
Related
I'm using the jQuery slider to change the value of an input.
div#slider
input#amount
I use the value of the input to perform some math with:
$("input#amount").change(function() {
...
The thing is, when I enter some value in the input, it works fine, but playing with the slider, the value appears to change, but no calculation is performed.
jsfiddle:
http://jsfiddle.net/mfeqoL7L/
Why/How to fix this?
Thx!
The problem is that setting a value on an input element using .val doesn't fire the change event: Why does the jquery change event not trigger when I set the value of a select using val()?
To manually fire the event call .change explicitly after setting the .val.
I am looking for a way to bind a function to a text box that executes when the text of the text box changed. I want to avoid the use of keyup or keypress, and other similar things. I don't want it to fire when I lose focus of it, just when the text changes. This needs to definitely work in IE browsers, and preferably work in other browsers.
Does anyone know which is the event to do this?
Thanks.
You might be able to try a setTimeout handler that just checks the value of that textbox every so often and will detect when it changes by comparing the current value to the last value.
I see that you've found a workaround but I just wanted to offer this anyways. Much more granular control.
$('#searchbox').on('keyup, keydown, change', function(e) {
if(e.keyCode!= 9 || e.keyCode!= 16 || e.keyCode!= 17 || e.keyCode!= 18){
//Find keys that you don't want triggering your event and add them in the IF statement above
//http://www.cambiaresearch.com/articles/15/javascript-char-codes-key-codes
//Put code here that calls AJAX
}
});
I would like to be able to detect when the selected value of dropdown has changed using jQuery. The selected value of the dropdown is changed by other JavaScript, so I want to be able to catch this event.
I can see the dropdown changing, however the following code does not capture the event correctly. Does the change event only capture the event when it is performed by the user and not other code?
$('select[name=b_country]').live('change', function() {
alert('the country dropdown has changed');
});
<select name="b_country" style="display: block;">
Yes, only user interactions fire the event. Otherwise you wouldn't be able to (re)set values in a listener without entering an infinite loop.
If you want to inform other (listening) scripts that you changed the value, you can manually trigger an event. With jQuery, this is easy:
$('select[name=b_country]').val(…).change();
Is there a way to detect when the value of a select list is set to empty by a javasscript and not by the user? It seems that the change-event only triggers by mouse or keyboard.
And is there a way to detect when the number of options in a select list changes (added, removed)?
You have to trigger the change event manually, when you are changing the value of a select with javascript. E.g:
$('#myselect').val(10).change();
In this example the value is set to 10 and the change event is triggered. If there is an event handler attached to the select, it will be executed.
Use Jquery's change function
$("#idofselect").change(function(){ });
To answer your first question, not it's not possible to detect what caused the change in the select list in the change event itself.
However, if there is javascript code changing the select list you could add some logic in there to perform the tasks needed in this scenario.
can I use blur in a hidden field in jquery? if not, how can I track changes in a hidden field
Hidden field is hidden, it won't be visible to a user to change something. Only page author/script can change its value and if that is the case, you can use the change event to track changes.
$('#hidden_id').change(function(){
alert('Changed Value: ' + $(this).val());
});
NO, you can't in it's normal behavior.
The onchange event occurs when a control loses the input focus (blur) and its value has been modified since gaining focus.
http://www.w3.org/TR/html401/interact/scripts.html#adef-onchange
But you can do it as Sarfraz suggested. Add onchange event then explicitly trigger it every time you change the value of the hidden typed input
The 'change()' event handler doesn't work on hidden input fields. What you can do instead is something along these lines (untested!):
function hiddenOnChange(elem, function) {
if ($(elem).val()!=$(elem).getAttr('oldVal')) {
function;
}
$(elem).attr('oldVal', $(elem).val());
window.setTimeout(function(){hiddenOnchange(elem, function);}, 100);
}
Call this function with your hidden input field and the onchange function. It re-creates the onchange function by comparing the field's "current" value with a previously stored value. If nothing is changed, it re-checks in 100 msecs; If something did change, it will execute your function (I hope ;))
Hope this helps.