The DOM query was done using document.getElementById(‘ _id_‘), which queries the document for elements with a matching id attribute. This is a frequently used event trigger for input fields. This means that whenever a change is made to the input, the handler function getChecked is called. In the above example the triggering DOM event is onchange. Take the following example, which creates a checkbox in the browser window and assigns a handler to the DOM event onchange:Ĭonst checkBox = document.getElementById('check1').checked Get the value of input type checkboxĪs mentioned above, retrieving the value of a checkbox field is slightly different from other input field types. If the input is of type checkbox, a checkbox appears. This type determines what the input element looks like when it is rendered on the page, If the input is of type text, a text field is shown on the browser. value attribute (more on this below).Įvery input has a type. Some inputs, however, require different attributes – for example, the checkbox input type does not use the. value attribute will prove useful in getting the field’s value. If there are several input fields, this simple query will not work well – you’ll want to use a more specific DOM query in that case.įor most input types, the. In the text input field example above, we used document.querySelector(‘input’) to find the input field being modified. There are several ways to do so – mainly by using different DOM queries. To specify your event handler, add it as an attribute on the element using the following format:Īt the script level, simply define your handler function:Įvent handlers often require that you find the HTML element being modified as the first step. Make sure that the DOM event you’ve chosen is the right choice for your input. Make sure that the DOM element has an event attribute that triggers your event handler function.ī. Working with event handlers properly requires effort at both the DOM level and at the Script level.Ī. For example, if you were typing the word “dog”, you would see “d”, then “do”, then finally “dog” in the console output. With oninput, every character the user types (or deletes) will trigger the getVal() function, causing the field’s contents to be printed to the console. If, for example, you are working with an input that supports a search mechanism, and the event handler should be triggered each time the data changes, you will want to use the oninput event. The onblur event triggers the getVal() function once the field loses focus (i.e. Understanding when these events are triggered, and how they interact with your input field, is the key to getting your event handlers working properly. On top of this, multiple events can be used with the same input. In the above example, we use the DOM event onblur to make calls to our event handler function.Įach type of input will require different events to trigger the handler function – that’s the part of retrieving input from the user that requires some thinking. The input’s value will be printed to the console when the getVal() function is invoked.Įvery input can receive an attribute that establishes a “call to action” – in other words, an event that triggers the execution of a function. It creates a text input field, then prints the contents to the consoleĬonst val = document.querySelector('input').value There are many types of input fields, and while getting their value is done similarly in each case, it requires some thought to do well. Input fields enable us to receive data from users.
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