<!DOCTYPE?html>
<html>
?<head>
??<title>?事件</title>??
??<script?type="text/javascript">
???function?count(){
????var?num1=document.getElementById("txt1"?).value;
????var?num2=document.getElementById("txt2"?).value;
????var?num3=document.getElementById("select"?).value;
????var?console="";
????switch(num3){
????????case?"+":console=parseInt(num1)+parseInt(num2)?break;
????????case?"-":console=parseInt(num1)-parseInt(num2)?break;
????????case?"*":console=parseInt(num1)*parseInt(num2)?break;
????????default:console=parseInt(num1)+parseInt(num2);
????}
????document.getElementById("fruit").value=console;
????//獲取第一個(gè)輸入框的值
????//獲取第二個(gè)輸入框的值
????//獲取選擇框的值
????//獲取通過下拉框來選擇的值來改變加減乘除的運(yùn)算法則
????//設(shè)置結(jié)果輸入框的值?
????
???}
??</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(diào)用創(chuàng)建的函數(shù)，得到結(jié)果-->?
???<input?type='text'?id='fruit'?/>???
?</body>
</html>
2015-12-01
<!DOCTYPE?html> <html> <head> ????<title>?事件</title> ????<script?type="text/javascript"> ????function?count()?{ ????????var?num1?=?document.getElementById("txt1").value; ????????var?num2?=?document.getElementById("txt2").value; ????????var?num3?=?document.getElementById("select").value; ????????var?console?=?""; ????????switch?(num3)?{ ????????????case?"+": ????????????//這塊缺少了分號，下同 ????????????????console?=?parseInt(num1)?+?parseInt(num2); ?????????????????break; ????????????case?"-": ????????????????console?=?parseInt(num1)?-?parseInt(num2); ?????????????????break; ????????????case?"*": ????????????????console?=?parseInt(num1)?*?parseInt(num2); ?????????????????break; ????????????default: ????????????????console?=?parseInt(num1)?+?parseInt(num2); ????????????????//這塊缺少了break ????????????????break; ????????} ????????document.getElementById("fruit").value?=?console; ????????//獲取第一個(gè)輸入框的值 ????????//獲取第二個(gè)輸入框的值 ????????//獲取選擇框的值 ????????//獲取通過下拉框來選擇的值來改變加減乘除的運(yùn)算法則 ????????//設(shè)置結(jié)果輸入框的值? ????} ????</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(diào)用創(chuàng)建的函數(shù)，得到結(jié)果--> ????<input?type='text'?id='fruit'?/> </body> </html>問題標(biāo)注出來了，修改后的代碼如上