提取URL中某一参数name的value

queryString: ?name=value&name1=&name2=value2

function getUrlQuery (name) {
	let reg = new RegExp('(^|&)'+name+'=([^&]*)(&|$)');
	let value = window.location.search.subStr(1).match(reg);
	return value[2]
}

function getUrlQuery(url, name) {
	let reg = new RegExp('(^|&)'+name+'([^&]*)(&|$))');
	let position = url.indexOf('?');
	let value = url.subStr(position++1).match(reg);
	return value[2];
}

let reg = new RegExp('(^|&)'+name+'=([^&]*)(&|$)')

1.^name=([^&]*)& //name=value&
2.&name=([^&]*)& //&name1=&
3.&name=([^&]*)$ //&name2=value2

let value = window.location.search.subStr(1).match(reg);