通过HTML按钮触发PHP函数

I have a conmysql.php with this function:

function addTeacher($idTeach,$nameTeacher,$teacherDay){


    $adicionar = sprintf("INSERT INTO `test`.`teacher` (`$idTeacher`, `$nameTeacher`, `$teacherDay`) VALUES ('$idTeacher', '$nameTeacher', '$teacherDay');");
    $queryadd  = mysql_query($adicionar);
}

I'm filling these variables with 3 forms, and it's working but i don't know how to trigger the addTeacher (); on a HTML button.

I should use AJAX? If yes, how?

Try like,

HTML

 <input type="button" id="addTeacher" value="Add teacher"/>

SCRIPT

$(function(){
    $('#addTeacher').on('click',function(){
        $.ajax({
           url:'conmysql.php',
           type:'POST',
           data:{type'addTeacher','name':'ABC','day':'day to add'},
           success:function(data){
              alert(data);
           }
        });
    });
});

PHP

function addTeacher($idTeach,$nameTeacher,$teacherDay){
    // Id of teacher should be primary and autoincrement 
    // so there is no need if teacher id
    $adicionar = sprintf("INSERT INTO `test`.`teacher` (`$idTeacher`, `$nameTeacher`, `$teacherDay`) VALUES ('$idTeacher', '$nameTeacher', '$teacherDay');");
    $queryadd  = mysql_query($adicionar);
}

if(isset($_POST['type']) and $_POST['type']=='addTeacher')
{
  addTeacher(1,$_POST['name'],$_POST['day']);
}

You can't call PHP functions from HTML.

You'll need to think of a solution where your HTML triggers the PHP page to run, one common method is to use AJAX to do this, although you could also do it in a form submit, it's up to you.