函數是否定義:
<script type="text/javascript">
try {
if(typeof FunName === "function") { //FunName為函數名稱
alert("is function");
} else {
alert("not a function");
}
} catch(e) {}
</script>
變量是否定義:
<script type="text/javascript">
try {
if(typeof myvalue==="undefined") { //myvalue為變量名稱
alert("is value");
} else {
alert("not a value");
}
} catch(e) {}
</script>