樓上，為什么startCount后面不用加（）

? var num=0;
? function startCount() {
??? document.getElementById('count').value=num;
??? num=num+1;
??? setTimeout("startCount()",1000);
? }
? window.onload=startCount;

?
? <script type="text/javascript">
?? function count(){
??? var oTxt1 = document.getElementById("txt1").value;
??? var oTxt2 = document.getElementById("txt2").value;
??? var oSlt = document.getElementById("select").value;
??? var result = "";
??? switch(oSlt) {
??????? case "+":
??????????? result = parseFloat(oTxt1) + parseFloat(oTxt2);
??????????? break;
??????? case "-":
??????????? result = parseFloat(oTxt1) - parseFloat(oTxt2);
??????????? break;
??????? case "*":
??????????? result = parseFloat(oTxt1) * parseFloat(oTxt2);
??????????? break;
??????? default:
??????????? result = parseFloat(oTxt1) / parseFloat(oTxt2);
??? }
??? document.getElementById("fruit").value = result;
?? ?
?? }
? </script>
?