JavaScript Mouse Events
Describe and identify JavaScript code that responds to onmouseover and onmouseout events.
How to study National 5 Computing Science
Move from functional requirements to designs and implementation, trace data and code carefully, and support testing and evaluation with evidence.
Core concepts
Concept 1
The onmouseover event occurs when the pointer moves onto an element.
Exam cue: Identify the event first, then the targeted element, property and assigned value.
Concept 2
The onmouseout event occurs when the pointer leaves an element.
Exam cue: Describe both the visible change and when it happens.
Concept 3
Event code can change an element’s content or appearance and should be traced from the correct trigger.
Risk pitfalls and guardrails
Reversing onmouseover and onmouseout.
Guardrail: Check option route, data type, valid boundary, loop condition, array index, identifier and expected output before committing to the response.
Describing JavaScript syntax without explaining the resulting page behaviour.
Guardrail: Check option route, data type, valid boundary, loop condition, array index, identifier and expected output before committing to the response.
Memory anchors
onmouseover
Run event code when the pointing device moves onto the element.
onmouseout
Run event code when the pointing device leaves the element.
Event target
Identify the page element whose event handler is activated.
Property change
Trace which content or style property receives a new value.
Paired events
One event can apply a change and the other can restore the original state.
Explain behaviour
Trigger + target + changed property + visible result.
Checkpoint rule
Do the check-up only after you can summarize each concept in one sentence and identify one dangerous pitfall from memory.
Knowledge Check (after reading)
Short check-up to confirm understanding of this module.
Check-up Questions
What does an anchor target such as #prices identify?
Why close nested HTML elements in the reverse order they opened?
Answer all questions to submit.
Next step personalized recommendations
Continue learning
Move forward only after this module is stable.
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