August 4, 2000 - Using the "onBlur" Event Handler | WebReference

August 4, 2000 - Using the "onBlur" Event Handler

Yehuda Shiran August 4, 2000
Using the "onBlur" Event Handler
Tips: August 2000

Yehuda Shiran, Ph.D.
Doc JavaScript

A blur event occurs when a text field loses focus. A field gains focus when the user clicks inside the text box, and the focus is lost when the user clicks outside the box, anywhere on the page. The onBlur event handler executes JavaScript code when a blur event occurs. The following text field demonstrates a usage of the onBlur event. Once you click inside the text field and leave (click outside anywhere on the page), you will be prompted to enter a value if the field is empty when you leave it:

Here is the script that implements this event handling:

function checkInput(element) {
  if (element.value == "") {
    alert("Please enter a value!");
// -->
<INPUT TYPE="text" NAME="myField" VALUE="" onBlur="checkInput(this)">

Notice that the dialog box is displayed only if you first access the field and then exits it without entering any value.