覆盖原execIt函数
修改后的execIt函数允许对多个正则表达式进行匹配(每个正则表达式一行)，并对每一个匹配成分显示出是第几个正则表达式匹配的。
这可视为语法分析的雏形，只要对匹配产生相应的动作。

function execIt(form) {
var mode
if(form.chkmode.checked) mode = "gi"
else mode = "g"
var regexpArray = form.regexp.value.split("\r\n") //获取正则表达式到数组

if(nextpoint == 0) form.reglist.value = "" var key = true if(form.scankmode.checked) key = false else nextpoint = 0 do { var offs = 9999999999 var pos = -1 var input = form.main.value.substr(nextpoint) //对每个正则表达式进行匹配 for(var i=0;i<regexpArray.length;i++) { re.compile(regexpArray[i],mode) var matchArray = re.exec(input) if(matchArray) { if(offs > matchArray.index) { offs = matchArray.index pos = i //保存距离起始位子最近的匹配 } } } if(pos>=0) { re.compile(regexpArray[pos],mode) var matchArray = re.exec(input) for(var i=1;i<matchArray.length;i++) matchArray[i] = "$"+i+":"+matchArray[i] form.reglist.value = "["+(pos+1)+"]"+(nextpoint+matchArray.index)+" => " + matchArray[0] +"\n"+form.reglist.value form.matchlist.value = "$0:"+matchArray.join("\n") nextpoint = nextpoint + matchArray.index + matchArray[0].length }else { if(!key) form.reglist.value = "没有找到\n" + form.reglist.value form.matchlist.value = " " nextpoint = 0 key = false } }while(key) }