CIS 119 Adding an event handler to a button

Objective

Use inline JavaScript to create an event handler

JavaScript code added as attribute value

Example:

Code:

// This code is contained in the head element or an external file

function displayHello() {
   alert("Hello");
}

// We can not attach an event handler to a button until after
//     the button is created, so this should not run until
//     after the window is loaded.
function init() {
   document.getElementById("HelloButton").onclick = displayHello;
}

// This code waits until the document is loaded to attach the 
//     event handler to the button.
// Note how the init function is used as an object and referred
//     to by using its name.
window.onload = init;