JavaScript 中函式原型
JavaScript 中建立的函式始終會擁有 JavaScript 引擎新增的原型屬性。原型屬性是一個物件,預設情況下包含建構函式屬性。可以透過以下方式訪問函式原型:-
functionName.prototype
當使用函式建構函式建立物件時,此原型屬性可用於在該函式建構函式建立的物件之間共享方法或屬性。
以下是 JavaScript 中函式原型的程式碼:
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;
}
.result {
font-size: 20px;
font-weight: 500;
color: blueviolet;
}
</style>
</head>
<body>
<h1>Function prototypes in JavaScript</h1>
<div class="result"></div>
<br />
<button class="Btn">Click Here</button>
<h3>Click on the above button to call the welcome method of person1 and person2 object</h3>
<script>
let resEle = document.querySelector(".result");
let BtnEle = document.querySelector(".Btn");
function personConstructor(fName, lName) {
this.fName = fName;
this.lName = lName;
}
personConstructor.prototype.welcome = function () {
return "Welcome " + this.fName + " " + this.lName;
};
let person1 = new personConstructor("Rohan", "Sharma");
let person2 = new personConstructor("Shawn", "Smith");
BtnEle.addEventListener("click", () => {
resEle.innerHTML = "person1.welcome() = " + person1.welcome() + "<br>";
resEle.innerHTML += "person2.welcome() = " + person2.welcome() + "<br>";
});
</script>
</body>
</html>輸出

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