The difference between this and $ (this) in jquery initially thought this and $ (this) to be a die carved out. But when I read, and coding, it's not always the same, here's the difference between this and $ (this). The difference between this and $ (this) in Ad:jquery $ ("#textbox"). Hover (function () {this.title = "Test"; }, Fucntion () {this.title = "OK"; } ); Here this is actually an HTML element (textbox), TextBox has the Text property, so it is absolutely no problem to write. But if you change this to $ (this) it is not the case, error--reported. This is the difference between this and $ (this). Error Code: $ ("#textbox"). Hover (function () {$ (this). title = "Test"; }, Function () {$ (this). title = "OK"; } ); The $ (this) here is a jquery object, and the jquery object does not have the title property, so it is wrong to write this. jquery has the attr () method to get/set the properties of Dom objects, so the correct way to do this is as follows: The correct code: $ ("#textbox"). Hover (function () {$ (t His). attr (' title ', ' Test '); }, Function () {$ (this). attr (' title ', ' OK '); } ); The advantage of using jquery is that it packs a variety of browser versions on DOM objects, so use $ (this) uniformly instead of this should be a comparisonA good choice. The difference between this and $ (this) in jquery is here