let a = document.querySelector('#b1').value;
console.log(`a: ${a}`);
document.querySelector('#b1').value = 10;
console.log(`a: ${a}`);
uj5u.com熱心網友回復：
正如評論中所說，
當您這樣做時，let a = document.querySelector('#b1').value; 它會決議該值并將其保存在變數 a 中。
這樣做，它不會被更新。要獲得實際值，您需要每次都獲得它。
像這樣：
let wrongWay = document.getElementById("foo").value; // Getting it the wrong way
let rightWay = document.getElementById("foo"); // Getting it the right way
console.log("wrong way value : " wrongWay);
console.log("right way value : " rightWay.value);
// Changing input value
document.getElementById("foo").value = "new value";
console.log("Changed value !");
console.log("wrong way value : " wrongWay); // The value isn't updated as it is saved as a string -> so it didn't get any update
console.log("right way value : " rightWay.value); // By getting it, you are sure to get the right value<input id="foo" type="text" value="old value" >轉載請註明出處，本文鏈接：https://www.uj5u.com/net/327703.html
標籤：javascript dom
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