Visually, there are actually three states a checkbox can be in: checked, unchecked, or indeterminate. HTML ... Opera; 所有主流浏览器都支持 onchange 属性。 定义和用法. Код скрипта. If you are not familiar with the ‘this’ keyword , here in this example it refers to the target that fired that event which is here the checkbox we want to grab. onchange="myFunction()">, W3Schools is optimized for learning and training. First, I am using the $(document).ready(); that I have told you about and inside it I added an anonymous function. Quando o formulário é enviado, o par de nome / valor de dados será subscribe=newsletter. All what we will have to do is give an id to the form , I gave it an id of myform, then use jQuery to grab and submit the form. I also added the same exact HTML code we used in the previous code , the only difference will be in our javascript code since in this example we will be using jQuery instead of plain javascript. The code that is inside the anonymous function will be run each time the event is fired. Se o atributo value for omitido, o valor padrão da caixa de seleção é on , portanto, os dados enviados nesse caso seriam subscribe=on. If you are not familiar with anonymous functions they are functions that are declared in runtime and the reason they are called anonymous is that you create them without giving them a name. I am sure most of you have seen a lot on the Internet which is when there is something hidden in the form , something like a section for extra information or feedback and you press on a checkbox to toggle it and show it or hide it . New … The example below uses onChange to alert the user to changes in the checkbox's state. Let's see examples with each of them. Getting value of HTML Checkbox from onclick/onchange events. Take the following example:In this example, we've got a name of subscribe, and a value of newsletter. For radiobuttons and checkboxes, the onchange event occurs when the checked state has been changed. We determine whether the checkbox is checked and can take action based on that.. Handling a Group of Checkboxes Onclick. HTML CheckBox Label is used to giving a selected option to the user. difference is that the onchange event also works on , , , , , , , , , , , , , , , , ,