JavaScript lastIndex 屬性
JavaScript 中的 lastIndex 屬性返回匹配發生時的索引位置,並且下一個匹配將僅從該位置重新開始。lastIndex 屬性僅在設定了“g”修飾符時才有效。
以下是 JavaScript 中 lastIndex 屬性的程式碼 -
示例
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
<title>Document</title>
<style>
body {
font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;
}
.sample,
.result {
font-size: 18px;
font-weight: 500;
color: red;
}
</style>
</head>
<body>
<h1>JavaScript lastIndex Property</h1>
<div class="sample">The king bought an expensive ring.</div>
<div style="font-weight: bold; color: black;" class="result"></div>
<button class="Btn">CLICK HERE</button>
<h3>
Click on the above button to find the index of 'ing' in the above string
</h3>
<script>
let sampleEle = document.querySelector(".sample");
let resultEle = document.querySelector(".result");
let regex = new RegExp("ing", "g");
regex.test(sampleEle.innerHTML);
document.querySelector(".Btn").addEventListener("click", () => {
resultEle.innerHTML +='"ing" found Current Index = ' + regex.lastIndex + "<br>";
regex.test(sampleEle.innerHTML);
resultEle.innerHTML += '"ing" found Current Index = ' + regex.lastIndex;
});
</script>
</body>
</html>輸出

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