January 13, 2001 - Cancelable Events | WebReference

January 13, 2001 - Cancelable Events

Yehuda Shiran January 13, 2001
Cancelable Events
Tips: January 2001

Yehuda Shiran, Ph.D.
Doc JavaScript

The e object holds a lot of information about the Netscape 6 event. The cancelable property, for example, reveals whether an event can be canceled by any of the event handler up and down the hierarchy. Possible values are true and false. Some events cannot be canceled. The following statement prints the cancelable property value to the status window:

window.status = e.cancelable;
The status window is shown on the bottom left corner of Netscape 6 window. Notice that you have to pass the e object as a parameter to those functions which reference it. In the following example, we pass the e object as a parameter to colorItTan():

<DIV ID="demoDiv" STYLE="position:relative; left:100px; top:20px; width:220px; 
height:25px; color:blue; background-color:yellow;">Click me with the left button! 
</DIV>
<SCRIPT LANGUAGE="JavaScript">
<!--
var demoObj;
function init() {
  demoObj = document.getElementById("demoDiv");
  demoObj.addEventListener("click", colorItTan, false);
}
function colorItTan(e) {
  demoObj.style.backgroundColor = "tan";
  window.status = e.cancelable;
}
onload = init; 
// -->
</SCRIPT>

Get on Netscape 6 browser and play with this demo. Click the left button and observe that the left button click is cancelable (true value is printed to the status window.)