12样式操作

<p id="p1" style="color: red;">666</p>

var pElement = document.getElementById('p1').getAttribute('style')
console.log(pElement)

var pElement = document.getElementById('p1')
console.log(pElement.style)

var stylesheetList = document.styleSheets
console.log(stylesheetList)

var i = document.getElementsByTagName('input')[0]
console.log(window.getComputedStyle(i))