简单正则表达式
<!doctype html>
<html>
<head><meta>
<title>Regex--正则简单demo</title>
</head>
<body>
</body>
<script>
/*
* demo1：
*“\1”指与第一个（）内的内容相同；
*/
var a= /^<(\w+)\s*\/?>(?:<\/\1>)?$/ ;
b1 = a.exec("<body>");
b2 = a.exec("<br/>");
b3 = a.exec("<div></div>");
alert(b1);
alert(b2);
alert(b3);
/*
* demo2：
*jquery源码中出现的正则的解读；
*/
core_pnum = /[\-+]?(?:\d*\.|)\d+(?:[eE][\-+]?\d+|)/.source; //核心语句，.source获得正则的表达式；
rnumsplit = new RegExp( "^(" + core_pnum + ")(.*)$", "i" );
rnumnonpx = new RegExp( "^(" + core_pnum + ")(?!px)[a-z%]+$", "i" ); //数字后不可直接跟‘px’；
rrelNum = new RegExp( "^([-+])=(" + core_pnum + ")", "i" );
rfxnum = new RegExp( "^(?:([-+])=|)(" + core_pnum + ")([a-z%]*)$", "i" )
//测试语句开始
var n = "123dsga";
alert(rnumsplit.exec(n));
var m = "123pp";
alert(rnumnonpx.exec(m));
var a = "+=11.111";
alert(rrelNum.exec(a));
var b = "-=100%"; // b="100abc";
alert(rfxnum.exec(b));
/*
* demo3：
*jquery源码中出现的正则的解读；
*/
//去除两边的空格；
rtrim = /^[\s\uFEFF\xA0]+|[\s\uFEFF\xA0]+$/g;
var a=" ad cd ";
//alert('x'+a.replace(rtrim,'')+'x');
//alert('x'+a+'x');
/*
* demo4：
*jquery源码中出现的正则的解读；
*/
// JSON RegExp
rvalidchars = /^[\],:{}\s]*$/;
rvalidbraces = /(?:^|:|,)(?:\s*\[)+/g;
rvalidescape = /\\(?:["\\\/bfnrt]|u[\da-fA-F]{4})/g;
rvalidtokens = /"[^"\\\r\n]*"|true|false|null|-?(?:\d\d*\.|)\d+(?:[eE][\-+]?\d+|)/g; //"[^"\\\r\n]*"
=>这部分不清楚；
//测试语句开始
var b = "\,:{}";
alert(rvalidchars.exec(b));
var c = "[add], [asdg]";
alert(rvalidbraces.exec(c));
var d='\\b'; //d='\\\/'; //d = "\\ua1aa";
alert(rvalidescape.exec(d));
var e='"n"'; //e='false'; //e ='1.1e-11';
alert(rvalidtokens.exec(e));
//未完，待续……
</script>
</html>
