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為什么這樣寫運(yùn)行不出來

??????? function checkone(){
??????????? // 任務(wù)3
??????????? var hobby = document.getElementsByName("hobby");
??????????? var j=parseInt(document.getElementById("wb").value);
??????????? if(j<0&&j>6) alert("請輸入0-6之間的數(shù)！");
??????????? else hobby[j-1].checked=true;
?????? ?
?????????? ?
??????? }
???????

慕粉4408527

2016-12-06

源自：JavaScript進(jìn)階篇 9-4

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qq_AllureLove_8 回答被采納 +3 積分
2016-12-06

if(j<0&&j>6) alert("請輸入0-6之間的數(shù)！");判斷的內(nèi)容改為j<0||j>6

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#1

慕粉4408527 提問者

非常感謝！

2016-12-06 回復(fù) 有任何疑惑可以回復(fù)我~

淺愛為我心
2016-12-06

var j=document.getElementById("wb").value;
?var hobby = document.getElementById("hobby"+j);
hobby.checked = true;???

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慕粉4408527 提問者
2016-12-06

<!DOCTYPE HTML>
<html>
??? <head>
??????? <meta http-equiv="Content-Type" content="text/html; charset=gb2312">
??????? <title>無標(biāo)題文檔</title>
??? </head>
?? ?
??? <body>
??????? <form>
????????? 請選擇你愛好:<br>
????????? <input type="checkbox" name="hobby" id="hobby1">? 音樂
????????? <input type="checkbox" name="hobby" id="hobby2">? 登山
????????? <input type="checkbox" name="hobby" id="hobby3">? 游泳
????????? <input type="checkbox" name="hobby" id="hobby4">? 閱讀
????????? <input type="checkbox" name="hobby" id="hobby5">? 打球
????????? <input type="checkbox" name="hobby" id="hobby6">? 跑步 <br>
????????? <input type="button" value = "全選" onclick = "checkall();">
????????? <input type="button" value = "全不選" onclick = "clearall();">
????????? <p>請輸入您要選擇愛好的序號，序號為1-6:</p>
????????? <input id="wb" name="wb" type="text" >
????????? <input name="ok" type="button" value="確定" onclick = "checkone();">
??????? </form>
??????? <script type="text/javascript">
??????? function checkall(){
??????????? var hobby = document.getElementsByTagName("input");
????????? // 任務(wù)1
?????? ?
????????? for(var i=0;1<hobby.length;i++){
????????????? if(hobby[i].type=="checkbox")
????????????? hobby[i].checked=true;
????????? }
????????? ?
??????? }
??????? function clearall(){
??????????? var hobby = document.getElementsByName("hobby");
?????????? ?
???????? // 任務(wù)2?? ?
??????????? for(var i=0;1<hobby.length;i++){
????????????? hobby[i].checked=false;
??????????? }?? ?
??????? }
?????? ?
??????? function checkone(){
??????????? // 任務(wù)3
??????????? var hobby = document.getElementsByName("hobby");
??????????? var j=parseInt(document.getElementById("wb").value);
??????????? if(j<0&&j>6) alert("請輸入0-6之間的數(shù)！");
??????????? else hobby[j-1].checked=true;
?????? ?
?????????? ?
??????? }
?????? ?
??????? </script>
??? </body>
</html>