function?count(){????
//獲取第一個輸入框的值????
var?a=parseInt(document.getElementById('txt1').value);	
//獲取第二個輸入框的	v
var?b=parseInt(document.getElementById('txt2').value);????
//獲取選擇框的值????
var?select=document.getElementById('select').value;????
var?result='';	
????switch(select){????????
????case?'+':result?=?a+b;?break;????????
????case?'-':result?=?a-b;?break;????????
????case?'*':result?=?a*b;?break;????????
????case?'/':result?=?a/b;?break;	
}????
//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?????
????document.getElementById('fruit').value=result;???
}