Using "onfocusin" together with the "onfocusout" event:
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 sets the background color to red.
<!DOCTYPE html> <html> <body> Enter your name: /*w w w. ja va 2s . c o m*/ <input type="text" id="myInput" onfocusin="focusFunction()" onfocusout="blurFunction()"> <script> // Focus = Changes the background color of input to yellow function focusFunction() { document.getElementById("myInput").style.background = "yellow"; } // No focus = Changes the background color of input to red function blurFunction() { document.getElementById("myInput").style.background = "red"; } </script> </body> </html>