send button value to Jquery AJAX with onclick()

is it possible to send a value from button to Jquery AJAX with onclick function ? I have tried something like this code, but not working. There is nothing on console log.

html

<button type="button" class="hapus_krs" onclick="hapus_krs(this.value)" value="1">x</button> 
<button type="button" class="hapus_krs" onclick="hapus_krs(this.value)" value="2">x</button>
<button type="button" class="hapus_krs" onclick="hapus_krs(this.value)" value="n">x</button> 

script

function hapus_krs() {
    var formData = {
        'id_mhs': $(this).val()
    };
    $.ajax({
            type: 'POST',
            url: '<?=base_url()?>akademik/hapus_krs',
            data: formData,
            dataType: 'json',
            encode: true
        })
        .done(function(data) {
            console.log(data);
        })
};