Js/jquery How to get text box input focus

  This article is mainly on the Js/jquery get text box input focus of the method is introduced, need friends can come to the reference, I hope to help you.

Method One,     code as follows:  function Checkform () {             IF (document.form1.tr ainingname.value== "") {                     alert ("Course name cannot be empty!") ");                      document.form1.trainingname.focus ();                      return false;             &NBSP {   }   method Two, jquery   code is as follows:       FUNCT Ion Checkform () {               var classlevel = $ ("#classLevel"). Val ();   & nbsp           var re =/^[1-9][0-9]*$/;               if (!re.test (classlevel) &&classlevel.length>0) {              alert ("Please enter the grade of integers greater than 0!") ");               $ ("#classLevel"). focus ();               return false;          }    }