Methods for operating arrays based on jQuery_jquery

jQuery provides two functions:

1.$.map(array,callback(element,index));

For each element in the array, call the callback() function, and finally return a new array, the original array remains unchanged

For example:

                                                                                                                                                                                                       What comes back is a new array
               return value * 2;
})

2. $.each(array,fn);

Mainly used to traverse arrays without modifying the array. It can be traversed for ordinary arrays or "key-value arrays".

This can be used directly in each function to represent the value of the current element.

For example: Get the selected item in the checkbox

                                                                                                                                        

$(function () {

var arr = [];

                                                                                                                                                      

                                                                                                                                                                         ​ 

arr[key] = value.text();

                                                                                                                        

                var lengtha = $('input[type=checkbox][checked=checked]').length; 🎜>

                                                                                                    

})