Hello.
I've been watching on several sites. Facebook, Dropbox and various frameworks that use css and js an effect that appears before text is loaded. I hope you understand. Thanks
This is a technique used in the user experience. A great article called The Illusion of Time (The Illusion of Time) explains very well how human perception of time can be "dribbled" using simple features like an animated gif, see the Facebook example below.
Buildingthisfeaturedependsonwhichframeworkorlibraryyouareusinginyourproject.
Thearticle Facebook content placeholder deconstruction content of Facebook) demonstrates how this technique is deconstructed using the same one used by Facebook.