var oTxt1 = document.getElementById('t1');

var oTxt2 = document.getElementById('t2');

var btn1 = document.getElementById('btn1');

var btn2 = document.getElementById('btn2');

​

btn1.onclick = function(){

  var re = /[你我他]/g;

  oTxt2.value = oTxt1.value.replace(re, '***');

};

​

btn2.onclick = function(){

  var re = /<[^<>]+>/g;

  oTxt2.value = oTxt1.value.replace(re, '');

};