html:
+
+
Small class summary:
1. Three methods of dynamically creating elements
1. Method 1: document.write (not recommended, use very little)
2. Method 2: innerHTML (for small cases)
3. Method 3: document.createElement (commonly used)
Two, document.createElement method related
1, document.createElement (create a new child element)
2. rolls.appendChild(ul) add child elements to the node
3. removeChild This is a method to delete child elements