我想在一个事件侦听器中检索选择元素的初始值和选择值。
我试图捏造一些东西,但它给出了两次第二个值。任何建议将不胜感激。
.HTML:
<span class="curr__parent">
<select class="add__currency">
<option value="HUF" selected>HUF</option>
<option value="EUR">EUR</option>
</select>
</span>
.JS:
document.querySelector('.curr__parent').addEventListener("change",changeCurrenc);
var changeCurrency = function(event){
var firstCurr = document.querySelector(".add__currency").value;
var secondCurr = event.target.value;
console.log(firstCurr);
console.log(secondCurr);
};`
多谢 萨比
您必须将初始值存储在事件处理程序范围之外,因为它仅在值更改后触发。
document.querySelector('.add__currency').addEventListener("change", function(e){
changeCurrency(e);
});
var firstCurr = document.querySelector(".add__currency").value;
var changeCurrency = function(event){
console.log('firstCurr:', firstCurr);
var secondCurr = event.target.value;
console.log('secondCurr:', secondCurr);
firstCurr = secondCurr;
};
<span class="curr__parent">
<select class="add__currency">
<option value="HUF" selected>HUF</option>
<option value="EUR">EUR</option>
</select>
</span>