Navigator 2.0, Internet Explorer 3.0
<INPUT TYPE="radio" a definition of the handler onClick="handler-statements"> radio.onclick a reference to the handler radio.onclick(); an explicit invocation of the handler
onclick() is an event handler invoked when the user clicks on a Radio button. This event handler is defined by the onClick attribute of the HTML <INPUT> tag that defines the Radio button. The value of this attribute may be any number of JavaScript statements, separated by semicolons; these statements will be executed when the user clicks on (i.e., checks or unchecks) the button.