JS中innerHTML、outerHTML、innerText、outerText的用法与区别

<div id="mydiv">
      <span style="color:red">span1</span> span2
</div>

var innerHTML = document.getElementById("mydiv").innerHTML;
var innerText = document.getElementById("mydiv").innerText; //Firefox不支持 
var outerHTML = document.getElementById("mydiv").outerHTML;
var outerText = document.getElementById("mydiv").outerText; //Firefox不支持 
console.info(innerHTML);  //输出<span style="color:red">span1</span> span2
console.info(innerText);  //输出span1 span2
console.info(outerHTML);  //输出<div id="mydiv"><span style="color:red">span1</span>span2</div>
console.info(outerText);  //输出span1 span2

console.info(document.getElementById('mydiv').innerHTML.replace(/<.+?>/gim,''));