dataset 使用

dataset.md

<div id="day2-meal-expense" 
  data-drink="coffee" 
  data-food="sushi" 
  data-meal="lunch">¥20.12</div>

var expenseday2 = document.getElementById('day2-meal-expense');  
var typeOfDrink = expenseday2.dataset.drink;

function hyphenate( str ) {
  return str.replace( hyphenateRE, '$1-$2' ).toLowerCase();
}

export const set = ( dom, name, value ) => {
  if ( dom.dataset ) {
    dom.dataset[name] = value;
  } else {
    dom.setAttribute( `data-${hyphenate( name )}`, value );
  }
};

export const get = ( dom, name ) => {
  if ( dom.dataset ) {
    return dom.dataset[name];
  }
  return dom.getAttribute( `data-${hyphenate( name )}` );
};