当元素获得焦点时如何执行操作

Posted 2021-02-25

jQuery('form')  
    .focusin(function(){  
        jQuery(this).addClass('focused');  
    });  
    .focusout(function(){  
        jQuery(this).removeClass('focused');  
    });  
 
//However, the preferred way to do this is using  
// .focus() and .blur()  
 
//For when an element loses it's focus use .blur()  
$('#target').blur(function() { 
  alert('Handler for .blur() called.'); 
}); 
 
//For when an element gains focus use .focus() 
$('#target').focus(function() { 
  alert('Handler for .focus() called.');  
});