test：验证
var param = /\s+/；
var str = 'xxxx';
param.test(str)
js常用正则表达式有：
var str = 'xxxx';
去除所有空格:
str = str.replace(/\s+/g,"");
去除两头空格:
str = str.replace(/^\s+|\s+$/g,"");
去除左空格：
str=str.replace( /^\s*/, '');
去除右空格：
str=str.replace(/(\s*$)/g, "");
Email
/^[a-zA-Z0-9]+([!"#$%&'()*+,./:;<=>?@\^_`{|}~-]?[a-zA-Z0-9])*@[a-zA-Z0-9]+([\_\-\.]?[a-zA-Z0-9]+)*\.([\-\_]?[a-zA-Z0-9])+(\.?[a-zA-Z0-9]+)?$/
