首頁猿問我想實(shí)現(xiàn)的效果是1-2=結(jié)果或者...

我想實(shí)現(xiàn)的效果是1-2=結(jié)果或者 2-1=結(jié)果為什么下面代碼實(shí)現(xiàn)不了？

JavaScript

陽火鍋 2017-12-21 17:07:53

<body><input type="button" value="1" onclick="one()" id="a1"><input type="button" value="2" onclick="two()" id="a2"><input type="button" value="-" onclick="add()" id="a3" ><input type="button" value="=" onclick="dy()" ><input type="text" value="" id="a4" ></body><script>var a_4 = ""function one(){? ?var a_1 = document.getElementById("a1").value? ? ? ? ? ? ? }function two(){? ?var a_2 = document.getElementById("a2").value? ? ? ? ? ? ? }function add(){? ? var a_3 = document.getElementById("a3").value? ? ? ? ? ? }function dy(){? ? ? ?document.getElementById("a4").value =?a_4? ? ? ? ? ? }</script>

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3 回答

已采納

h5

TA貢獻(xiàn)19條經(jīng)驗(yàn) 獲得超9個(gè)贊

<body>

<input?type="button"?value="1"?onclick="one()"?id="a1">

<input?type="button"?value="2"?onclick="two()"?id="a2">

<input?type="button"?value="-"?onclick="minus()"?id="a3"?>
<input?type="button"?value="+"?onclick="add()"?id="a5"?>

<input?type="button"?value="="?onclick="dy()"?>
<input?type="button"?value="c"?onclick="cl()"?>

<input?type="text"?value=""?id="a4"?>

</body>

<script>

var?a_4?=?""
function?cl(){
	a_4=""
	document.getElementById("a4").value?=?a_4
}
function?one(){

????a_4?+=?document.getElementById("a1").value
document.getElementById("a4").value?=?a_4
??????????????}

function?two(){

???a_4?+=?document.getElementById("a2").value
document.getElementById("a4").value?=?a_4
??????????????}

function?minus(){

????a_4?+=?document.getElementById("a3").value
document.getElementById("a4").value?=?a_4
?}
?function?add(){

????a_4?+=?document.getElementById("a5").value
document.getElementById("a4").value?=?a_4
?}

function?dy(){

???????document.getElementById("a4").value?=?eval(a_4)
a_4=document.getElementById("a4").value
????????????}

</script>

反對回復(fù) 2017-12-21

陽火鍋
a_4+沒看懂什么意思，還有eval(a_4)不明白是什么。。我看不懂你的代碼，但我想你應(yīng)該懂我想問什么問題。。

回復(fù) 2017-12-21
h5
代碼拷貝過去運(yùn)行一下可以看到效果

回復(fù) 2017-12-25

堂堂堂堂糖糖糖童鞋

TA貢獻(xiàn)101條經(jīng)驗(yàn) 獲得超58個(gè)贊

<script>
????var?a_4?=?""
????var?numbers?=?[]
????function?one?()?{
????????var?a_1?=?document.getElementById("a1").value
????????numbers.push(a_1)
????}
????function?two()?{
????????var?a_2?=?document.getElementById("a2").value
????????numbers.push(a_2)
????}
????function?add()?{
????????if?(!numbers.length)?{
????????alert('請先選擇一個(gè)數(shù)字')
????????return?
????????}
????????var?a_3?=?document.getElementById("a3").value
????????numbers.push(a_3)
????}
????function?dy()?{
????????if?(numbers.length?!==?3)?{
????????????alert('操作有誤')
????????????return?
????????}
????????if?(numbers[1]?===?'-')?{
????????????a_4?=?numbers[0]?*?1?-?numbers[2]?*?1
????????}
????????document.getElementById("a4").value?=?a_4
????}
</script>

2 反對回復(fù) 2017-12-21

千秋此意

TA貢獻(xiàn)158條經(jīng)驗(yàn) 獲得超188個(gè)贊

<html>

<head>
????<meta?charset="utf-8">
????<title>test</title>
</head>

<body>
????<input?type="button"?value="1"?onclick="one(this.value)"?id="a1"?/>
????<input?type="button"?value="2"?onclick="one(this.value)"?id="a2"?/>
????<input?type="button"?value="-"?onclick="calc(this.value)"?id="a3"?/>
????<input?type="button"?value="="?onclick="dy()"?/>
????<input?type="button"?value="cls"?onclick="cls()"?/>
????<input?type="text"?value=""?id="a4"?readonly?/>
</body>
<script>
????var?a4?=?document.getElementById('a4');
????var?c?=?true;

????a4.value?=?'';

????function?one(val)?{
????????if?(c?===?false)?{
?????????????cls();
????????}
????????a4.value?+=?val;
????}

????function?calc(operator)?{
????????if?(/\d/.test(a4.value.substr(-1))?&&?c)?{
????????????a4.value?+=?operator;
????????}?else?{
????????????alert('請輸入正確的表達(dá)式!');
????????}
????}

????function?dy()?{
????????if?(!c?||?!(/^\d+.*\d+$/g.test(a4.value)))?return;
????????a4.value?+=?('='?+?new?Function('return?'?+?a4.value)());
????????c?=?false;
????}

????function?cls()?{
????????c?=?true;
????????a4.value?=?'';
????}
</script>

</html>

反對回復(fù) 2017-12-21