COMS 201 MSUM Event Handlers Prototype JQuery & JavaScript frameworks Worksheet

1. What are event handlers attached to in the DOM? Give an example.

2. Prototype and JQuery are JavaScript frameworks. What problems do frameworks help solve in JavaScript?

3. Describe how these events work in JavaScript.

• blur
• keypress
• load
• mousemove

Refer to HTML DOM Event Object (w3schools.com)

4. window.onload = function() {
var gameButtons = $$(“#game > button.control”);
for (var i = 0; i < gameButtons.length; i++)
{
gameButtons[i].observe(“click”, gameButtonClick);
}
};

Describe what this event handler function is designed to do.

5. Event handlers can accept an optional parameter to represent the event that is occurring.

Describe these two methods / properties of event handlers.

• element()
• stop()

6. Describe the follow events and their purpose.

• dblclick
• mouseout

What mouse event object properties exist in the browser? List 2 properties and their description.