JavaScript onclick function only works once (very simple code)
Question
I know there are many topics about this, but they address some variable issue. Mine is much more simple, but it is not working. Only works once.
var bt1; document.addEventListener('DOMContentLoaded', load); function load() { document.body.innerHTML += '<div>welcome</div>'; bt1 = document.getElementById('bt1'); bt1.onclick = clicked; } function clicked() { document.body.innerHTML += '<div>welcome</div>'; }
<body> <button id="bt1">Click me</button> </body>
I tried taking the clicked function in and out of the onclick statement (as some other topics suggested).
I also tried moving the bt1 variable declaration around (and not using a variable at all).
2 answers
solution1
4 2018-11-13 04:26:01
Whenever you assign to the innerHTML of a container (even if you're just concatenating with existing HTML), the container's contents will be removed , and the new innerHTML string will be parsed and then rendered by the browser. So, listeners that used to be attached to anything inside of the container will no longer work.
const container = document.querySelector('#container'); const child = container.children[0]; // Before: the child's parent is the `container`, as expected: console.log(child.parentElement); container.innerHTML += ''; // After: the child has no parent element! // If a listener was attached to the child before, // the child will no longer even be in the document! console.log(child.parentElement);
<div id="container"> <div>child</div> </div>
For what you're doing, either use insertAdjacentHTML , which will not corrupt listeners, but will perform similar functionality to innerHTML += :
var bt1; document.addEventListener('DOMContentLoaded', load); function load() { document.body.innerHTML += '<div>welcome</div>'; bt1 = document.getElementById('bt1'); bt1.onclick = clicked; } function clicked() { document.body.insertAdjacentHTML('beforeend', '<div>welcome</div>'); }
<body> <button id="bt1">Click me</button> </body>
Or, explicitly create the new element to append, and use appendChild :
var bt1; document.addEventListener('DOMContentLoaded', load); function load() { document.body.innerHTML += '<div>welcome</div>'; bt1 = document.getElementById('bt1'); bt1.onclick = clicked; } function clicked() { const div = document.createElement('div'); div.textContent = 'welcome'; document.body.appendChild(div); }
<body> <button id="bt1">Click me</button> </body>
solution2
0 2018-11-13 07:31:36
Another quick fix would be to reattach the listener in clicked mehtod.
var bt1; document.addEventListener('DOMContentLoaded', load); function load() { document.body.innerHTML += '<div>welcome</div>'; bt1 = document.getElementById('bt1'); bt1.onclick = clicked; } function clicked(a) { document.body.innerHTML += '<div>welcome</div>'; bt1 = document.getElementById('bt1'); bt1.onclick = clicked; }
<body> <button id="bt1">Click Me</button> </body>
solution3
0 2022-08-13 12:13:36
I'm having the same trouble. However, I'm not looking to concatenate anything.
In my simply written script, a simply function is created. I use the seconds to create a random number between 0 and 30; Then I put the function in button so that when I click the button, the random is written into a DIV element.
However, the onclick only works on the initial click, and there aren't any scripting errors in the console.
Example script: var time = new Date(); //function to create random number function chngTstFld(){ var ss = time.getSeconds(); var random_Number = ss; if(ss>30){ random_Number = random_Number - 30}; function chngTstFld(){ var ss = time.getSeconds(); var random_Number = ss; if(ss>30){ random_Number = random_Number - 30}; document.getElementById("tstFld").innerHTML = random_Number};
I want to replace the number with a new number in the DIV as many times as I click the button.
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