摘要：
<!DOCTYPE html><html> <head> <meta charset="utf-8"> <title>let的经典案例</title> <style> .item{ border: 1px solid aquamarine; width: 100px; height: 100px; 阅读全文
摘要：
<!DOCTYPE html><html> <head> <meta charset="utf-8"> <title></title> </head> <body> <script> // 变量声明 let a; let b,c,d; let e = 100; let f = 521, g = 'h 阅读全文