// JavaScript Document++++++++++++++++++++++++++++

function ChDsp(flg,ch,pref){
    var obj=document.all && document.all(ch) || document.getElementById && document.getElementById(ch);
    if(obj && obj.style){
        if(flg){
            obj.style.display = "block";
        } else {
            obj.style.display = "none";
            document.mainForm.course_id.value="";
            if(pref){
              var opt = document.getElementById('targetoption');
              var ch = opt.getElementsByTagName('input');
              for( i=0 ; i<48 ; i++ ) {
                ch[i].checked = false;
              }
            }
        }
    }
}