I would like to create a button using Javascript but why does the upB.onClick = testUp() not work?
<button class="up_btn" onClick="testUp()">Up</button>
var upB = document.createElement('button');
upB.classList.add("up_btn");
upB.innerText = "Up";
upB.onClick = testUp();
I would use upB.setAttribute('onclick','testUp()') ;
var upB = document.createElement('button');
upB.classList.add("up_btn");
upB.innerText = "Up";
upB.setAttribute('onclick','testUp()') ;
document.body.appendChild(upB);
function testUp(){alert('testUp')}EDIT : following suggestion in comment, please see snippet below with addEventListener.
var upB = document.createElement('button');
upB.classList.add("up_btn");
upB.innerText = "Up";
upB.addEventListener("click", testUp, false);
document.body.appendChild(upB);
function testUp(){alert('testUp')}