........

var?Txt1?=?parseInt(?document.getElementById('txt1').value?);

//獲取第二個輸入框的值

????var?Txt2?=?parseInt(??document.getElementById('txt2').value?);

//獲取選擇框的值

????var?Select?=??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?result?=?'';

......

? document.getElementById('fruit').value?=?result;

......

?<input?type='text'?id='txt1'?/>?

???<select?id='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'?/> ??

.......