<!doctype html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Document</title>
</head>
<body>
<br/><br/>
<input type="text" id="regtxt"/>
<br/>
<button onclick="getreg()">操作正則表達式/^fo+$/</button>
<button onclick="getreg1()">操作正則表達式/^fo*$/</button>
<button onclick="getreg2()">操作正則表達式/^fo?$/</button>
<div id="div1"></div>
<script>
// ^:一個字符串的開始 $：一個字符串的結束
function getreg(){
var reg=/^fo+$/;
//限制字符串長度，這里無法獲得輸入框的數據
var div1 = document.getElementById('div1');
var regtxt = document.getElementById('regtxt');
div1.innerHTML=reg.test(regtxt.value);
}
function getreg1(){
var reg=/^fo*$/;
var div1 = document.getElementById('div1');
var regtxt = document.getElementById('regtxt');
div1.innerHTML=reg.test(regtxt.value);
}
function getreg2(){
var reg=/^fo?$/;
var div1 = document.getElementById('div1');
var regtxt = document.getElementById('regtxt');
div1.innerHTML=reg.test(regtxt.value);
}
</script>
</body>
</html>
