JavaScript Tutorial/Development/Exception — различия между версиями
Admin (обсуждение | вклад) м (1 версия) |
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Текущая версия на 08:24, 26 мая 2010
Содержание
Array index to large exception
<html>
<head>
<title>Try Catch Example</title>
<script type="text/javascript">
try {
var arrErrors = new Array(10000000000000000000000); //causes error
arrErrors.push(exception);
} catch (oException) {
alert("An exception occurred.");
} finally {
alert("All done.");
}
</script>
</head>
<body>
</body>
</html>
Check Exception type with instanceof operator
<html>
<head>
<title>Try Catch Example</title>
<script type="text/javascript">
try {
eval("a ++ b"); //causes SyntaxError
} catch (oException) {
if (oException instanceof SyntaxError) {
alert("Syntax Error: " + oException.message);
} else {
alert("An unexpected error occurred: " + oException.message);
}
}
</script>
</head>
<body>
</body>
</html>
Check the exception name and output exception message
<html>
<head>
<title>Try Catch Example</title>
<script type="text/javascript">
try {
eval("a ++ b"); //causes SyntaxError
} catch (oException) {
if (oException.name == "SyntaxError") {
alert("Syntax Error: " + oException.message);
} else {
alert("An unexpected error occurred: " + oException.message);
}
}
</script>
</head>
<body>
</body>
</html>
Exception handler will bypass the statements
<html>
<head>
<title>Try Catch Example</title>
<script type="text/javascript">
try {
window.nonExistentFunction();
alert("Method completed.");
} catch (oException) {
alert("An exception occurred: " + oException.message);
} finally {
alert("End of try�catch test.");
}
</script>
</head>
<body>
</body>
</html>
Get Exception message
<html>
<head>
<title>Try Catch Example</title>
<script type="text/javascript">
try {
window.nonExistentFunction();
alert("Method completed.");
} catch (oException) {
alert("An exception occurred: " + oException.message);
} finally {
alert("End of try�catch test.");
}
</script>
</head>
<body>
</body>
</html>
Get Exception name
<html>
<head>
<title>Try Catch Example</title>
<script type="text/javascript">
try {
window.nonExistentFunction();
} catch (oException) {
alert("An exception occurred: " + oException.name);
} finally {
alert("End of try�catch test.");
}
</script>
</head>
<body>
</body>
</html>
Syntactic exception
<html>
<head>
<title>Try Catch Example</title>
<script type="text/javascript">
try {
eval("a -==-++ b"); //causes error
} catch (oException) {
alert("An exception occurred.");
} finally {
alert("All done.");
}
</script>
</head>
<body>
</body>
</html>
Throw exception out of a function
<html>
<head>
<title>Try Catch Example</title>
<script type="text/javascript">
function addTwoNumbers(a, b) {
throw new Error("Two numbers are required.");
}
try {
result = addTwoNumbers(90);
} catch (oException) {
alert(oException.message);
}
</script>
</head>
<body>
</body>
</html>