onmouseover attribute is one of the most commonly
used event attributes. It captures the moment that a cursor crosses the
boundary of an element, moving from outside to inside the element to which
the attribute is applied. It differs from the
onmousemove attribute, which is used to detect movement
within the element’s boundaries. Once the cursor is positioned over the
onmouseover event remains active until
the cursor is moved beyond the element’s boundaries—an event that the
onmouseout attribute would capture.
onmouseover attribute is mostly used to render
visual effects such as image swapping or color changes, and has been used
Note that this event attribute cannot be applied to the following elements:
The example below shows a simple image swap technique, whereby mousing over the image causes the image to change to one that reveals a location on a map:
<div> <img src="map.gif" alt="Hover to reveal the location on the map" onmouseover="this.src='map_location_revealed.gif';" onmouseout="this.src='map.gif';"/>Figures for February’s racing. </div>
This attribute has no fixed value.
It’s up to the author to decide on the scripting that’s included here, be
that a call to one or more defined functions, or a simple
Every browser listed supports this attribute. However, inline event handlers such as this should be avoided. In the same way that inline CSS styles are frowned upon but externally defined CSS styles are considered good practice, inline event handlers should be stripped out and replaced with events attached unobtrusively through the DOM.