Das Beispiel in diesem Artikel beschreibt, wie JavaScript den Ereignis-Proxy verwendet, um Tabellenzeilen hervorzuheben. Teilen Sie es als Referenz mit allen. Die spezifische Implementierungsmethode lautet wie folgt:
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>Highlight Rows</title>
<style type="text/css">
table {
background-color: lightgreen;
}
#third {
background-color: yellow;
}
</style>
</head>
<body>
<!-- Demonstrating "Event Delegation" to highlight table' rows
on mouseover.
Arguments can be passed via the delegate.
My site:andrew.dx.am -->
<table id="thetable" summary="highlight demo">
<tr><td>Just one</td><td>.. no another</td></tr>
<tr><td>Second</td><td>.. no another</td></tr>
<tr id="third"><td>A third</td><td>.. no another</td></tr>
<tr><td>Fourth for luck</td><td>.. no another</td></tr>
</table>
<script type="text/javascript">
var addEvent = function (elem, eventType, func) {
if ( elem.addEventListener )
addEvent = function (elem, eventType, func) {
elem.addEventListener(eventType, func, false);
};
else if ( elem.attachEvent )
addEvent = function (elem, eventType, func) {
elem.attachEvent('on' + eventType, func);
};
addEvent(elem, eventType, func);
};
var delegateEvent = function (elem, childElems, eventType, func, args) {
addEvent(elem, eventType, function (e) {
var evt = e || window.event;
var elem = evt.target || evt.srcElement;
if ( elem.nodeName.toLowerCase() == childElems.toLowerCase() ) {
func(elem, args);
}
});
};
function highlightRows(obj, args) {
if (args && args.over) {
obj.prevColour = obj.parentNode.style.backgroundColor;
obj.parentNode.style.backgroundColor = args.colour;
if (args.index && obj.title == "")
obj.title = "Row " + obj.parentNode.rowIndex;
} else {
obj.parentNode.style.backgroundColor = "";
if (obj.title.indexOf("Row ") + 1)
obj.title = "";
}
}
function init() {
delegateEvent(document.getElementById('thetable'), 'td', 'mouseover',
highlightRows, {'colour': 'lightblue', 'over': true,
'index': true});
delegateEvent(document.getElementById('thetable'), 'td', 'mouseout',
highlightRows, {'over': false});
}
addEvent(window, 'load', init);
</script>
</body>
</html>
Ich hoffe, dass dieser Artikel für das JavaScript-Programmierdesign aller hilfreich sein wird.
