list, which are 1, 2, 3, 4, 4, 5, and 5, respectively.

for the first time, delete the 0th data 1, I change from 0 to 1, and the list becomes 2, br 3, 4, 5, 6
eq (1) is the second data 3, then 3 is deleted, I becomes 2, the list becomes 2, 4, 5, eq (2) is the third data 5

try this. You can delete all the selected ones without looping.

$(".checkboxdele:checked").parent().parent().remove()

the reason is that after you delete a piece of data, the length of the array changes, and your I still adds an iMel-to the PP,if establishment

$('dele').click(function(){
    for(....){
        ....
        if(){
            .....
            i--;
        }
    }
})