revision:
This attribute fires the moment an element loses focus. "Onblur" is most often used with form validation code (e.g. when the user leaves a form field).
The "onblur attribute" is the opposite of the "onfocus attribute".
The onblur attribute is part of the event attributes, and can be used on any HTML element.
<element onblur="script"></element>
script: the script to be run on onblur.
Enter your name:
When you leave the input field, a function is triggered which transforms the input text to upper case.
<p class="spec">Enter your name: <input type="text" name="fname" id="fname" onblur="changeFocus()"></p>
<p class="spec">When you leave the input field, a function is triggered which
transforms the input text to upper case.</p>
<script>
function changeFocus() {
var x = document.getElementById("fname");
x.value = x.value.toUpperCase();
}
</script>
<form style="margin-left:3vw;" name="onblur_example" action="">
Name : <input type="text" name="name" onblur="alert('name field has lost focus')"><br><br>
<label>Favorite sports </label>
<select name="favourite_sports" onblur="alert('favourite_sports has lost focus')">
<option value="Soccer">Soccer</option>
<option value="Hockey">Hockey</option>
<option value="Tennis">Tennis</option>
<option value="Golf">Golf</option>
</select><br><br>
<label>Describe yourself in short : </label><br><textarea cols="20" rows="10" name="describe_ yourself"
onblur="alert('describe_ yourself has lost focus')"></textarea><br><br>
<button type="button" name="submit">Submit</button>
</form>