var c= "b";
var aaa=['北京(bj)','上海(sh)','重庆(cq)','成都(cd)','北海(bh)'];
var reArr = GetItemFromArr(aaa,c);
for(var i = 0;i <reArr.length;i++) alert(reArr[i]);

function GetItemFromArr(a,word)
{//从数组a提取包含word的项
    var Str = a.join("");
    var re = new RegExp("([^\)]+)\(" + word + "[^\)]*\)","ig");
    return Str.match(re);
}

var aaa = "['北京(bj)','上海(sh)','重庆(cq)','成都(cd)','北海(bh)']";

function getWord(str,key)
{
    var re = new RegExp("[\"']([^,(]*)\\(" + key + "\\w*\\)[\"']","ig");
    var arr = [];
    while(re.exec(str))
        arr[arr.length] = RegExp.$1;
    return arr;
}
alert(getWord(aaa,"b"));
alert(getWord(aaa,"c"));
alert(getWord(aaa,"cq"));
alert(getWord(aaa,"ca"));

var aaa = ['北京(bj)','上海(sh)','重庆(cq)','成都(cd)','北海(bh)'];
var ccc = aaa.toString();


function getWord(str,key)
{
    //var re = new RegExp("[\"']([^,(]*)\\(" + key + "\\w*\\)[\"']","ig");
    var re = new RegExp("(?:^|,)([^(]*)\\(" + key + "\\w*\\)","ig");
    var arr = [];
    while(re.exec(str))
        arr[arr.length] = RegExp.$1;
    return arr;
}

alert(getWord(ccc,"b"));
alert(getWord(ccc,"c"));
alert(getWord(ccc,"cq"));
alert(getWord(ccc,"ca"));