为什么这段实现数量增加的代码运行提示Cannot read property 'value' of undefined"
//script
var addd = document.getElementsByClassName("add");
for(var n=0;n<addd.length;n++){
addd[n].onclick=function(){
var j = document.getElementsByClassName("count-input");
var h = parseInt(j[n].value)
j[n].value=h+1;
}
//html
<tr><td>
<input class="count-input" value="1"/>
<span class="add">+</span>
</td></tr>
<tr><td>
<input class="count-input" value="1"/>
<span class="add">+</span>
</td></tr>
79351浏览 2235回答 4
4回答
-
QQ_随意
作用域问题(function(n){addd[n].onclick=function(){ var j = document.getElementsByClassName("count-input"); var h = parseInt(j[n].value) j[n].value=h+1;}})(n)加个闭包就行了 -
慕田峪6141110
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
79351
<!DOCTYPE html><html> <head> <meta charset="UTF-8"> <title></title> <style type="text/css"> .count{ width: 90px; } .reduce{ width: 17px; height: 23px; background-color: gainsboro; float: left; border: 1px solid #e5e5e5; line-height: 23px; } .count-input{ width: 50px; height: 15px; float: left; text-align: center; border: 1px solid #aaa; color: #343434; padding: 4px 0; } .add{ width: 17px; height: 23px; background-color: gainsboro; float: left; text-align: center; line-height: 23px; border: 1px solid #e5e5e5; } </style> </head> <body> <table> <tr > <td class="count"> <span class="reduce"></span> <input class="count-input" value="1"/> <span class="add">+</span> </td> </tr> <tr > <td class="count"> <span class="reduce"></span> <input class="count-input" value="1"/> <span class="add">+</span> </td> </tr> </table> <script type="text/javascript"> var addd = document.getElementsByClassName("add"); for(var n=0;n<addd.length;n++){ addd[n].onclick=function(){ var j = document.getElementsByClassName("count-input"); var h = parseInt(j[n].value) j[n].value=h+1; }} </script> </body></html> -
qq_佛说过过过_0
我这边并没有报错，你把代码贴全了，我运行看看。 -
慕粉3166282
没有那个属性
随时随地看视频慕课网APP
相关分类
JavaScript