How to pass arguments to addEventListener listener function?

Question

The situation is somewhat like-

var someVar = some_other_function();
someObj.addEventListener(\"click\", function(){
    some_function(someVar);
}, false);
<         


        

Answer 1

You need:

newElem.addEventListener('click', {
    handleEvent: function (event) {
        clickImg(parameter);
    }
});

Answer 2

nice one line alternative

element.addEventListener('dragstart',(evt) => onDragStart(param1, param2, param3, evt));

function onDragStart(param1, param2, param3, evt) {

 //some action...

}

Answer 3

Use

   el.addEventListener('click',
    function(){
        // this will give you the id value 
        alert(this.id);    
    },
false);

And if you want to pass any custom value into this anonymous function then the easiest way to do it is

 // this will dynamically create property a property
 // you can create anything like el.<your  variable>
 el.myvalue = "hello world";
 el.addEventListener('click',
    function(){
        //this will show you the myvalue 
        alert(el.myvalue);
        // this will give you the id value 
        alert(this.id);    
    },
false);

Works perfectly in my project. Hope this will help

Answer 4

One way is doing this with an outer function:

elem.addEventListener('click', (function(numCopy) {
  return function() {
    alert(numCopy)
  };
})(num));

This method of wrapping an anonymous function in parentheses and calling it right away is called an IIFE (Immediately-Invoked Function Expression)

You can check an example with two parameters in http://codepen.io/froucher/pen/BoWwgz.

catimg.addEventListener('click', (function(c, i){
  return function() {
    c.meows++;
    i.textContent = c.name + '\'s meows are: ' + c.meows;
  }
})(cat, catmeows));

Answer 5

There is a special variable inside all functions: arguments. You can pass your parameters as anonymous parameters and access them (by order) through the arguments variable.

Example:

var someVar = some_other_function();
someObj.addEventListener("click", function(someVar){
    some_function(arguments[0]);
}, false);

Answer 6

You can just bind all necessary arguments with 'bind':

root.addEventListener('click', myPrettyHandler.bind(null, event, arg1, ... ));

In this way you'll always get the event, arg1, and other stuff passed to myPrettyHandler.

http://passy.svbtle.com/partial-application-in-javascript-using-bind