1. Regular expressions
1
2
3
4
//删除开头和结尾所有的空格  
function trim(str) {  
  return str.replace(/(^\s+|\s+$)/g,''); 
}
1
2
3
4
5
6
7
注： 
^ 开头 
$ 结尾 
\s 空格匹配 
+ 多次出现      
g 全文匹配 
i 忽略大小写  
  1. setTimeout(message, 3000);

Execute the function message once after 3 seconds. If you want to repeat the execution, you need to call setTimeout again in the message function