<!DOCTYPE?html>
<html>
?<head>
??<title>?事件</title>??
??<script?type="text/javascript">
???function?count(){
???????
????//獲取第一個輸入框的值
????var?firstNumber=document.getElementById("txt1").value;
//獲取第二個輸入框的值
????var?sencondNumber=document.getElementById("txt2").value;
//獲取選擇框的值
????var?selectValue=document.getElementById("select").value
//獲取通過下拉框來選擇的值來改變加減乘除的運算法則
????var?sum="";
????switch(seletValue){
????????case"+":
????????????sum=parseInt(firstNumber)+parseInt(secondNumber);
????????????break;?
????????case"-":
????????????sum=parseInt(firstNumber)-parseInt(secondNumber);
????????????break;
????????case"*":
????????????sum=parseInt(firstNumber)*parseInt(secondNumber);
????????????break;
????????default:?sum=parseInt(firstNumber)/parseInt(secondNumber);
????????break;
????};
????//設置結果輸入框的值?
????document.getElementById("fruit").value=sum;
????
???}
??</script>?
?</head>?
?<body>
???<input?type='text'?id='txt1'?/>?
???<select?id='select'>
<option?value='+'>+</option>
<option?value="-">-</option>
<option?value="*">*</option>
<option?value="/">/</option>
???</select>
???<input?type='text'?id='txt2'?/>?
???<input?type='button'?value='?=?'?onclick="count()"/>?<!--通過?=?按鈕來調用創建的函數，得到結果-->?
???<input?type='text'?id='fruit'?/>???
?</body>
</html>
2016-10-17
<!DOCTYPE?html> <html> ?<head> ??<title>?事件</title>?? ??<script?type="text/javascript"> ???function?count(){ ???????var?txt1=document.getElementById("txt1").value; ???????var?txt2=document.getElementById("txt2").value; ???????var?select=document.getElementById("select").value; ???????var?resule; ????switch(select) ????{ ????????case?"+":resule=parseInt(txt1)+parseInt(txt2);break; ????????case?"-":resule=parseInt(txt1)-parseInt(txt2);break; ????????case?"*":resule=parseInt(txt1)*parseInt(txt2);break; ????????case?"/":resule=parseInt(txt1)/parseInt(txt2);break;??????? ????} ????document.getElementById("fruit")=result; ???} ??</script>? ?</head>? ?<body> ???<input?type='text'?id='txt1'?/>? ???<select?id='select'> <option?value='+'>+</option> <option?value="-">-</option> <option?value="*">*</option> <option?value="/">/</option> ???</select> ???<input?type='text'?id='txt2'?/>? ???<input?type='button'?value='?=?'?onclick=count()?/>?<!--通過?=?按鈕來調用創建的函數，得到結果-->? ???<input?type='text'?id='fruit'?/>??? ?</body> </html>2016-10-16
?var firstNumber=document.getElementById("txt1").value;
? ? //獲取第二個輸入框的值
? ? var sencondNumber=document.getElementById("txt2").value;
? ? //獲取選擇框的值
? ? var selectValue=document.getElementById("select").value
? ? //獲取通過下拉框來選擇的值來改變加減乘除的運算法則
? ? var sum="";
? ? switch(seletValue){
? ? ? ? case"+":
? ? ? ? ? ? sum=parseInt(firstNumber)+parseInt(secondNumber);
? ? ? ? ? ? break;?
? ? ? ? case"-":
? ? ? ? ? ? sum=parseInt(firstNumber)-parseInt(secondNumber);
? ? ? ? ? ? break;
? ? ? ? case"*":
? ? ? ? ? ? sum=parseInt(firstNumber)*parseInt(secondNumber);
? ? ? ? ? ? break;
? ? ? ? case"/":
? ? ? ? ? ? sum=parseInt(firstNumber)/parseInt(secondNumber);
? ? ? ? break;
? ? };
? ? //設置結果輸入框的值?
? ? document.getElementById("fruit").value=sum;
? ? ?
? ?}