js/jquery method to obtain input focus of text box_javascript skills

Method 1,

Copy the code The code is as follows:

function CheckForm() {
           if (document.form1.trainingName.value==""){
                                                                                                                                                                                                                                                          ; );
                                       return false; 🎜> Copy the code


The code is as follows:

function CheckForm() {
var classLevel = $("#classLevel").val(); var re = /^[1-9][0-9]*$/;

if(!re.test( classLevel)&&classLevel.length>0){                                     alert("Please enter an integer greater than zero!"); > } }