Is property assessor good or evil? C# thinks good and Java as contrast. What about JavaScript? Maybe yes, Maybe no...
Mozilla SpiderMonkey introduce variety of solutions for getter and setter. Here is the sample:
<html>
<head>
<script type="text/ecmascript">
function trace(msg) {
document.getElementById('console').innerHTML += msg + '<br />';
}
</script>
</head>
<body>
<div id="console" class="debug"></div>
<script type="text/ecmascript" src="test-js-getset.js">
</script>
</body>
</html>
test-js-getset.js
=================
function test1() {
var obj = {
prop getter: function () { return 'prop1'; }
};
trace(obj.prop);
obj.prop getter = function () { return 'prop2'; }
trace(obj.prop);
obj.prop getter = getter function () { return 'prop3'; }
trace(obj.prop);
}
function test2() {
function MyObj() {
this.__defineGetter__('prop', function () { return 'prop1'; });
}
var obj = new MyObj();
trace(obj.prop);
obj.__defineGetter__('prop', function () { return 'prop2'; });
trace(obj.prop);
}
function test3() {
var obj = {
foo: null,
get prop() { return 'prop1'; },
set prop(v) { trace(v); },
bar: null,
};
trace(obj.prop);
obj.prop = 'hello';
}
test1();
test2();
test3();
Unfortunately, M$ IE supports no one of above. And even codes of test1() and test3() will cause syntax error. Only test2() can be interpreted by IE, u can catch the exception for the absence of __defineGetter__. But nothing else can u do, because I found no solution of emulating __defineGetter__ in IE, though there are some tricks to make a object with properties via wrap vbscript or introduce htc.
