首頁猿問加減乘除運算為什么沒有結(jié)果顯示

加減乘除運算為什么沒有結(jié)果顯示

JavaScript

qq_天空下起了魚_0 2017-06-05 16:02:16

<!DOCTYPE html><html>?<head>? <title> 事件</title> ?? <script type="text/javascript">? ?function count(){? var Txt1=document.getElementById("txt1"); ?? var Txt2=document.getElementById("txt2");? var Select=document.getElementById("select");??var result;?? switch(Select)?{ case "+":? ? ? ? result=parseInt(Txt1.value)+parseInt(Txt2.value);? ? ? ? break;? ?case "-";?? ? ? ? result=parseInt(Txt1.value)-parseInt(Txt2.value);? ? ? ? break;? ? case "*":? ? ? ? result=parseInt(Txt1.value)*parseInt(Txt2.value);? ? ? ? break;? ? default:? ? result=parseInt(Txt1.value)/parseInt(Txt2.value);? break;?} ?document.getElementById("fruit").value=result;? ?}??? </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>

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3 回答

李曉健

TA貢獻1036條經(jīng)驗獲得超461個贊

function?count(){
????var?Txt1=document.getElementById("txt1");
????var?Txt2=document.getElementById("txt2");
????var?Select=document.getElementById("select");

????var?result;
????//這里要取值
????switch(Select.value)
????{?case?"+":
????????result=parseInt(Txt1.value)+parseInt(Txt2.value);
????????break;
????????//這里是?:?不是?;
????????case?"-":
????????????result=parseInt(Txt1.value)-parseInt(Txt2.value);
????????????break;
????????case?"*":
????????????result=parseInt(Txt1.value)*parseInt(Txt2.value);
????????????break;
????????default:
????????????result=parseInt(Txt1.value)/parseInt(Txt2.value);
????????????break;
????}
????document.getElementById("fruit").value=result;

}

看注釋

反對回復 2017-06-05

李曉健

TA貢獻1036條經(jīng)驗獲得超461個贊

function?count(){
????var?Txt1=document.getElementById("txt1");
????var?Txt2=document.getElementById("txt2");
????var?Select=document.getElementById("select");

????var?result;
????//這里要取值
????switch(Select.value)
????{?case?"+":
????????result=parseInt(Txt1.value)+parseInt(Txt2.value);
????????break;
????????//這里是?:?不是?;
????????case?"-":
????????????result=parseInt(Txt1.value)-parseInt(Txt2.value);
????????????break;
????????case?"*":
????????????result=parseInt(Txt1.value)*parseInt(Txt2.value);
????????????break;
????????default:
????????????result=parseInt(Txt1.value)/parseInt(Txt2.value);
????????????break;
????}
????document.getElementById("fruit").value=result;

}

看注釋

反對回復 2017-06-05