JavaScript click event listener on class

Question

I m currently trying to write some JavaScript to get the attribute of the class that has been clicked  I know that to do this the correct way  I should use an event listener   My code is as follows   var classname   document getElementsByClassName  classname     var myFunction   function         var attribute   this getAttribute  data-myattribute        alert attribute       classname addEventListener  click   myFunction    false     I was expecting to get an alert box every time I clicked on one of the classes to tell me the attribute but unfortunately this does not work  Can anyone help please    Note - I can quite easily do this in jQuery but I would NOT like to use it

User · Answer

Yow can use querySelectorAll to select all the classes and loop through them to assign the eventListener  The if condition checks if it contains the class name  const arrClass   document querySelectorAll  quot  className quot    for  let i of arrClass      i addEventListener  quot click quot    e    gt        if  e target classList contains  quot className quot              console log  quot Perfrom Action quot

User · Answer

With modern JavaScript it can be done like this   x000D   x000D  const divs   document querySelectorAll   a     divs forEach el   gt  el addEventListener  click   event   gt      console log event target getAttribute  data-el          x000D   lt  DOCTYPE html gt   lt html gt   lt head gt     lt meta charset  utf-8  gt     lt meta name  viewport  content  width device-width  gt     lt title gt Example lt  title gt     lt style gt       a         background-color red        height  33px        display  flex        align-items  center        margin-bottom  10px        cursor  pointer                  b         background-color  00AA00        height  50px        display  flex        align-items  center        margin-bottom  10px           lt  style gt   lt  head gt   lt body gt     lt div class  a  data-el  1  gt 1 lt  div gt     lt div class  b  data-el  no-click-handler  gt 2 lt  div gt     lt div class  a  data-el  3  gt 11 lt  div gt   lt  body gt   lt  html gt  x000D   x000D   x000D    Gets all elements by class name Loops over all elements with using forEach Attach an event listener on each element Uses event target to retrieve more information for specific element

User · Answer

You can use the code below   document body addEventListener  click   function  evt        if  evt target className      databox             alert this           false

User · Answer

This should work  getElementsByClassName returns an array Array-like object see edit  of the elements matching the criteria   var elements   document getElementsByClassName  classname     var myFunction   function         var attribute   this getAttribute  data-myattribute        alert attribute       for  var i   0  i  lt  elements length  i          elements i  addEventListener  click   myFunction  false       jQuery does the looping part for you  which you need to do in plain JavaScript   If you have ES6 support you can replace your last line with       Array from elements  forEach function element          element addEventListener  click   myFunction             Note  Older browsers  like IE6  IE7  IE8  don  t support getElementsByClassName and so they return undefined     EDIT   Correction  getElementsByClassName doesnt return an array  but a HTMLCollection in most  or a NodeList in some browsers  Mozilla ref   Both of these types are Array-Like   meaning that they have a length property and the objects can be accessed via their index   but are not strictly an Array or inherited from an Array   meaning other methods that can be performed on an Array cannot be performed on these types   Thanks to user  Nemo for pointing this out and having me dig in to fully understand

User · Answer

Also consider that if you click a button  the target of the event listener is not necessaily the button itself  but whatever content inside the button you clicked on  You can reference the element to which you assigned the listener using the currentTarget property  Here is a pretty solution in modern ES using a single statement      document querySelectorAll  quot  myClassName quot   forEach i   gt  i addEventListener           quot click quot           e   gt                alert e currentTarget dataset myDataContent

User · Answer

This was edited to allow for children of the target class to trigger the events  See bottom of the answer for details     An alternative answer to add an event listener to a class where items are frequently being added and removed  This is inspired by jQuery s on function where you can pass in a selector for a child element that the event is listening on   var base   document querySelector   base       the container for the variable content var selector     card      any css selector for children  base addEventListener  click   function event         find the closest parent of the event target that      matches the selector   var closest   event target closest selector     if  closest  amp  amp  base contains closest            handle class event           Fiddle  https   jsfiddle net u6oje7af 94   This will listen for clicks on children of the base element and if the target of a click has a parent matching the selector  the class event will be handled  You can add and remove elements as you like without having to add more click listeners to the individual elements  This will catch them all even for elements added after this listener was added  just like the jQuery functionality  which I imagine is somewhat similar under the hood    This depends on the events propagating  so if you stopPropagation on the event somewhere else  this may not work  Also  the closest function has some compatibility issues with IE apparently  what doesn t     This could be made into a function if you need to do this type of action listening repeatedly  like  function addChildEventListener base  eventName  selector  handler      base addEventListener eventName  function event        var closest   event target closest selector       if  closest  amp  amp  base contains closest              passes the event to the handler and sets  this           in the handler as the closest parent matching the          selector from the target element of the event       handler call closest  event                                                             EDIT  This post originally used the matches function for DOM elements on the event target  but this restricted the targets of events to the direct class only  It has been updated to use the closest function instead  allowing for events on children of the desired class to trigger the events as well  The original matches code can be found at the original fiddle  https   jsfiddle net u6oje7af 23

[javascript] JavaScript click event listener on class

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