Summary of mistakes for beginners in js

Beginner JavaScript found some beginner mistakes, summarized here.
1. Use semicolons to
  end a line of statements without adding ";", but you must add ";" between two statements on the same line.
2. Two ways to call object keys
  var phone={zone;'010',number;'1234567'}
  var phone-number=phone['zone']+phone.number;
  console.log(phone-number);
  Output: 0101234567
3.x==y;//Is the comparison value equal
  x===y;//Is the comparison value and type equal
4.The difference between let and var is
  mainly reflected in
  the variables defined by different vars in the scope Global variables or function variables
  The variables defined by let are block-level variables or local variables
5. The method of adding a key-value pair to the hash table   table name
  [key]=value =ages[key] 7. Find the value   object name of a key in the object. Key 8. Jump statement   break Jump out of the current loop   continue to end this loop 9. The difference between while and do-while   while first judges the condition, and then executes the statement









  do-while executes the statement first, and then judges the condition
10. Any type added to a string will be converted to a string type