通過getElementsByClassName JavaScript查找列表的匹配實例

Question

我想檢查列表值，在實例化匹配值的情況下，我想交換元素名稱。 我正在嘗試以這種方式進行操作，但無法正常工作。

 <!DOCTYPE html> <html> <body> <button onclick="myFunction()">Try it</button> <div class="aa"><ul><li class="a">a</li><li class="a">b</li><li class="a">c</li></ul></div> <div class="aa"><ul><li class="a">s</li><li class="a">b</li><li class="a">c</li></ul></div> <script> function myFunction() { var x = document.getElementsByClassName("a")[0]; for (var i = 0; i < x.length; ++i) { if (x.getElementsByClassName("a")[i].innerHTML == "a") { x[i].innerHTML = "Hello World!"; alert("YO"); } } } </script> </body> </html>

Answer 1

您需要這樣做，在這里：

從document.getElementsByClassName("a")[0];刪除[0] document.getElementsByClassName("a")[0];
從(x.getElementsByClassName("a")[i].innerHTML刪除.getElementsByClassName("a")

這將首先允許您遍歷所有a ，然后使用x[i].innerHTML測試其內容。

堆棧片段

 <!DOCTYPE html> <html> <body> <button onclick="myFunction()">Try it</button> <div class="aa"> <ul> <li class="a">a</li> <li class="a">b</li> <li class="a">c</li> </ul> </div> <div class="aa"> <ul> <li class="a">b</li> <li class="a">a</li> <li class="a">c</li> </ul> </div> <script> function myFunction() { var x = document.getElementsByClassName("a"); for (var i = 0; i < x.length; ++i) { if (x[i].innerHTML == "a") { x[i].innerHTML = "Hello World!"; } } } </script> </body> </html>

如果你想獲得只有a那就是后人aa ，嘗試用querySelectorAll()

堆棧片段

 <!DOCTYPE html> <html> <body> <button onclick="myFunction()">Try it</button> <div class="aa"> <ul> <li class="a">a</li> <li class="a">b</li> <li class="a">c</li> </ul> </div> <div class="aa"> <ul> <li class="a">b</li> <li class="a">a</li> <li class="a">c</li> </ul> </div> <script> function myFunction() { var x = document.querySelectorAll(".aa .a"); for (var i = 0; i < x.length; ++i) { if (x[i].innerHTML == "a") { x[i].innerHTML = "Hello World!"; } } } </script> </body> </html>

如果使用getElementsByClassName() ，則需要2個循環

 <!DOCTYPE html> <html> <body> <button onclick="myFunction()">Try it</button> <div class="aa"> <ul> <li class="a">a</li> <li class="a">b</li> <li class="a">c</li> </ul> </div> <div class="aa"> <ul> <li class="a">s</li> <li class="a">a</li> <li class="a">c</li> </ul> </div> <script> function myFunction() { var x = document.getElementsByClassName("aa"); console.log(x.length); for (var i = 0; i < x.length; ++i) { var y = x[i].getElementsByClassName("a"); for (var ii = 0; ii < y.length; ++ii) { if (y[ii].innerHTML == "a" ) { y[ii].innerHTML = "Hello World!"; } } } } </script> </body> </html>

Answer 2

這是兩次潛水的版本

 <!DOCTYPE html> <html> <body> <button onclick="myFunction()">Try it</button> <div class="aa"> <ul> <li class="a">a</li> <li class="a">b</li> <li class="a">c</li> </ul> </div> <div class="aa"> <ul> <li class="a">s</li> <li class="a">a</li> <li class="a">c</li> </ul> </div> <script> function myFunction() { var x = document.getElementsByClassName("aa"); console.log(x.length); for (var i = 0; i < x.length; ++i) { var y = document.getElementsByClassName("a"); for (var i = 0; i < y.length; ++i) { if (y[i].innerHTML == "a" ) { y[i].innerHTML = "Hello World!"; } } } } </script> </body> </html>

通過getElementsByClassName JavaScript查找列表的匹配實例

問題描述

2 個解決方案

解決方案1
1 已采納 2018-04-18 18:39:16

解決方案2
0 2018-04-18 18:48:19

通過getElementsByClassName JavaScript查找列表的匹配實例

問題描述

2 個解決方案

解決方案1 1 已采納 2018-04-18 18:39:16

解決方案2 0 2018-04-18 18:48:19

解決方案1
1 已采納 2018-04-18 18:39:16

解決方案2
0 2018-04-18 18:48:19