首頁猿問運(yùn)算結(jié)果出錯(cuò)

運(yùn)算結(jié)果出錯(cuò)

JavaScript

rk10133 2016-12-23 17:02:11

<!DOCTYPE?html> <html> ?<head> ??<title>?事件</title> ??<script?type="text/javascript"> ???function?count(){ ????var?a=document.getElementById("txt1").value; ????//獲取第一個(gè)輸入框的值 ????var?b=document.getElementById("txt2").value; ????//獲取第二個(gè)輸入框的值 ????var?c=document.getElementById("fruit").value; ????//獲取選擇框的值 ????var?answer ????switch(c){ ????????case"+": ????????????answer=parseInt(a)+parseInt(b); ????????????break; ????????case"-": ????????????answer=parseInt(a)-parseInt(b); ????????????break; ????????case"*": ????????????answer=parseInt(a)*parseInt(b); ????????????break; ????????default: ????????????answer=parseInt(a)/parseInt(b); ????} ????//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 ????document.getElementById("fruit").value=answer; ????//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()"/>? ???<input?type="text"?id="fruit"/> ?</body> </html>

查看完整描述

1 回答

已采納

流逝在指尖活在當(dāng)下

TA貢獻(xiàn)4條經(jīng)驗(yàn) 獲得超1個(gè)贊

獲取值錯(cuò)誤了，沒有獲取到運(yùn)算符號(hào)的值，可以打開瀏覽器控制臺(tái)，打印變量查看

打印變量值得方法，可以直接在控制臺(tái)中查看

console.log(c)

var?c=document.getElementById("fruit").value;

第十一行改為

var?c=document.getElementById("select").value;

<!DOCTYPE?html>
<html>
?<head>
??<title>?事件</title>
??<script?type="text/javascript">
???function?count(){
????var?a=document.getElementById("txt1").value;
????//獲取第一個(gè)輸入框的值
????var?b=document.getElementById("txt2").value;
????//獲取第二個(gè)輸入框的值
????var?c=document.getElementById("select").value;
????//獲取選擇框的值
????var?answer
????switch(c){
????????case"+":
????????????answer=parseInt(a)+parseInt(b);
????????????break;
????????case"-":
????????????answer=parseInt(a)-parseInt(b);
????????????break;
????????case"*":
????????????answer=parseInt(a)*parseInt(b);
????????????break;
????????default:
????????????answer=parseInt(a)/parseInt(b);
????}
????//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
????document.getElementById("fruit").value=answer;
????//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>

反對(duì) 回復(fù) 2016-12-23