document.write('<form id="form1">');
document.write('敵のLv：<input type="text" id="lv" value="13">←半角で入力 ');
document.write('<input type="button" value="計算開始" onClick="calc()"><br>');
document.write('<div id="result">');
document.write('ここに結果が表示されます。');
document.write('</div>');
document.write('</form1>');

var acList = new Array(10, 5, 0, -5, -10, -15, -20, -25, -30, -35, -40, -45, -50);

var _lv = new Object;
_lv = document.getElementById("lv");

var _result = new Object;
_result = document.getElementById("result");

var thtml;
var tnum;
var tlv;

function calc(){
 tlv = parseInt(_lv.value);
 var tnum;

 thtml = '<table border><tr><th>PC側のAC</th><th>1回攻撃</th><th>2回攻撃</th><th>3回攻撃</th><th>4回攻撃</th><th>5回攻撃</th></tr>';
 for(i = 0; i < acList.length; i++){
  tnum = calc2(acList[i]);
  thtml += '<tr><td align="center">' + acList[i] + '</td><td align="right">' + tnum + '%</td>';
  thtml += '<td align="right">' + calc3(2, tnum) + '%</td>';
  thtml += '<td align="right">' + calc3(3, tnum) + '%</td>';
  thtml += '<td align="right">' + calc3(4, tnum) + '%</td>';
  thtml += '<td align="right">' + calc3(5, tnum) + '%</td></tr>';
 }
 thtml += '</table>';

 _result.innerHTML = thtml;
}

function calc2(ac){
 var tnum = 22 - ac - tlv;
 if(tnum > 21) tnum = 21;
 if(tnum < 1) tnum = 1;
 return Math.round((1 - tnum / 22) * 10000) / 100;
}

function calc3(attack, pnum){
 var tnum = 1 - pnum / 100;
 var tnum2 = tnum;
 for(j = 1; j < attack; j++){
  tnum2 *= tnum;
 }
 return Math.round((1 - tnum2) * 10000) / 100;
}