document.getElementsByClassName不起作用

Question

Does anyone know why it isn't working?

I want it to show div odpoved when I click on div dotaz .

 function ukaz(a) { var elements = document.getElementsByClassName(a); for (var i = 0; i < elements.length; i++) { elements[i].style.display = "block"; } } 

 <div class="dotaz" onClick="ukaz(odpoved)"> <p>YOSODJDN</p> <span class="qanick">jirka</span> <span class="fafadown"><i class="arrow fa fa-angle-down" style="font-size:24px"></i></span> </div> <div class="odpoved" style="display:none"> <p>ODPOVED</p> <span class="qanick">anetka</span> </div> 

Answer 1

Use it like this, pass odpoved as a string

<div class="dotaz" onClick="ukaz('odpoved')">

 <div class="dotaz" onClick="ukaz('odpoved')"> <p>YOSODJDN</p> <span class="qanick">jirka</span> <span class="fafadown"><i class="arrow fa fa-angle-down" style="font- size:24px"></i></span> </div> <div class="odpoved" style="display:none"> <p>ODPOVED</p> <span class="qanick">anetka</span> </div> <script> function ukaz(a) { var elements = document.getElementsByClassName(a); for (var i = 0; i < elements.length; i++) { elements[i].style.display = "block"; } } </script> 

Answer 2

onClick="ukaz(odpoved)" is attempting to call a function, using a variable - instead of a string - as an argument.

 function ukaz(a) { var elements = document.getElementsByClassName(a); for (var i = 0; i < elements.length; i++) { elements[i].style.display = "block"; } } 

 <div class="dotaz" onClick="ukaz('odpoved')"> <!-- odpoved is a string, not a variable --> <p>YOSODJDN</p> <span class="qanick">jirka</span> <span class="fafadown"> <i class="arrow fa fa-angle-down" style="font-size:24px"></i> </span> </div> <div class="odpoved" style="display:none"> <p>ODPOVED</p> <span class="qanick">anetka</span> </div>