Javascript DOM onfocusin Event in event bubbling

Introduction

Event delegation: setting the useCapture parameter of addEventListener() to true for focus and blur:

When you enter the input field, a function is triggered which sets the background color to yellow.

When you leave the input field, a function is triggered which removes the background color.

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<!DOCTYPE html>
<html>
<body>
<form id="myForm">
  <input type="text" id="myInput">
</form>/*from  w  w  w. ja v a  2s .c o  m*/

<script>
var x = document.getElementById("myForm");
x.addEventListener("focus", myFocusFunction, true);
x.addEventListener("blur", myBlurFunction, true);

function myFocusFunction() {
  document.getElementById("myInput").style.backgroundColor = "yellow";
}

function myBlurFunction() {
  document.getElementById("myInput").style.backgroundColor = "";
}
</script>

</body>
</html>



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