How to access jquery change event value outside the method?

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I have an input text field:

<input type="text" id="from_input" class="form-control" placeholder="FROM">

I want to get the value of text when it changes. Here is my jquery code:

<script>
  var fromValue;
  $(document).ready(function(){
    $("#from_input").change(function() {
      fromValue = $(this).val();
    });
    console.log(fromValue);
  });
</script>

I am getting fromValue variable as undefined. I need to get the text field value for further calculation in whole script. How can I achieve this?

You are logging the fromValue variable before the change event has fired.

Your code needs to be updated to log the variable inside of the closure:

<script>
  var fromValue;
  $(document).ready(function(){
    $("#from_input").change(function() {
      fromValue = $(this).val();
      console.log(fromValue);
    });
  });
</script>

If you attempt to access fromValue outside of this inner function, it will be undefined. Only within the inner function (more precisely, after the inner function is called) will it have a value.

If you want to use the value, you'll need to pass it from inside the function, e.g.

$("#from_input").change(function() {
  do_something($(this).val());
});

where do_something is defined elsewhere in the code and performs the further calculation you're trying to do.

You should read up on closures as that's what you're dealing with here.

Accessing variables outside of function?, then it makes sense to get undefined. when you click button 2 before clicking button one, myVar is currently set to the value undefined. when you� jQuery change() Method triggers the change event, when the value of an html element has been changed. The elements covered by this method are <input>, <textarea> and <select>, if the value of any of these elements is changed then the change() method triggers change event. jQuery change() Method attaches these html elements (<input>, <textarea> and <select>) to the event handler function and

A example:

$(function() {
  $('#itext').keyup(function() {
    var text = $(this).val();
    $('#result').text('Your text: ' + text);
  });
});
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<input type="text" id="itext">
<br><label id="result">Your text: </label>

.change(), This method is a shortcut for .on( "change", handler ) in the first two variations, and .trigger( The change event is sent to an element when its value changes. The change event occurs when the value of an element has been changed (only works on <input>, <textarea> and <select> elements). The change() method triggers the change event, or attaches a function to run when a change event occurs. Note: For select menus, the change event occurs when an option is selected. For text fields or text areas, the change event occurs when the field loses focus, after the content has been changed.

You can use the event argument. The event contains the target element. And I noticed that you console.log is outside the callback function. Your code probably works already but you just don't see it.

<script>
  var fromValue;
  $(document).ready(function(){
    $("#from_input").change(function(event) {
      fromValue = event.target.value;
      console.log(fromValue);
    });
  });
</script>

.triggerHandler(), triggerHandler( "event" ) method will not call .event() on the element it is triggered triggerHandler() returns whatever value was returned by the last handler it� We have used change() method which occurs when the element changes. The line $(“#myval”).change(function()) binds a function to change event. document.getElementById() method accesses the element with specified value of the Id or Name attribute.Its going to access the element by using id #myval and displays

event.data, Example: Within a for loop, pass the value of i to the .on() method so that the current� For this reason, the relevant event handlers will not be executed. If you want to execute them, you should call .trigger( "change" ) after setting the value. The .val() method allows setting the value by passing in a function. As of jQuery 1.4, the function is passed two arguments, the current element's index and its current value:

jQuery, In the below code, no function is passed to the change method. of “ GeeksforGeeks” to the “Enter Value:” box and clicking outside of the box-. The current DOM element within the event bubbling phase: event.data: Contains the optional data passed to an event method when the current executing handler is bound: event.delegateTarget: Returns the element where the currently-called jQuery event handler was attached: event.isDefaultPrevented()

It attaches an onchange event handler to run when the jQuery change event occurs, or invokes said event. Usage of .change() Explained. The .change() jQuery method attaches an event handler, invoked when the value of an input element (such as <input>, <textarea>, <select>) changes. See the example below and enter anything in the field or check a

Comments
  • fromValue will only have some value when #from_input is changed... You'll need to change your logic or maybe trigger a change on #from_input before logging the variable