如何使变量<span id="price"></span>与 JavaScript 一起使用？
必须在长 HTML 页面中嵌入许多 VARS，并且需要在长页面中嵌入变量。
想不通。
getPrice = function() {
var price = Number(document.getElementById("price").value);
var pout = Number(document.getElementById("pout").value) / 100;
var sellingprice = price;
var coop = price * pout;
var fsbo = price * pout;
var hret = price * .02;
var others = price * .06;
var saves = others - hret;
document.getElementById("sellingprice").value = sellingprice.toFixed(2);
document.getElementById("hret").value = hret.toFixed(2);
document.getElementById("fsbo").value = fsbo.toFixed(2);
document.getElementById("others").value = others.toFixed(2);
document.getElementById("saves").value = saves.toFixed(2);
}<!DOCTYPE html>
<html>
<body>
<input id="price"> :Price
<br><br>
<input id="pout">%
<br><br>
<button onclick="getPrice()"> Calculate </button>
<br><br>
<span id="price"></span>
TEST: Price: $<input readonly id="sellingprice"><br>
FSBO $<input readonly id="fsbo"><br>
HRET $<input readonly id="hret"><br>
OTHERS $<input readonly id="others"><br>
SAVE $<input readonly id="saves"><br>
</body>
</html>您有两个元素具有相同的id
<span id="price"></span>
和
<input id="price"> :Price
正因为如此，每当您点击计算时，它都会尝试从不可用的span中获取值，因此返回为未定义，因此您的所有值都可能NaN。
此外value属性仅适用于用于输入的元素。span没有value属性，您可能需要查看innerText或innerHTML。
每个元素必须具有唯一的id。下面是具有不同 idspan的代码工作示例。
<!Doctype html>
<html>
<body>
<input id="price"> :Price
<br><br>
<input id="pout">%
<br><br>
<button onclick="getPrice()"> Calculate </button>
<br><br>
<span id="spanprice"></span> TEST: Price: $<input readonly id="sellingprice"><br> FSBO $<input readonly id="fsbo"><br> HRET $<input readonly id="hret"><br> OTHERS $<input readonly id="others"><br> SAVE $<input readonly id="saves"><br>
<script>
getPrice = function() {
var price = Number(document.getElementById("price").value);
var pout = Number(document.getElementById("pout").value) / 100;
var sellingprice = price;
var coop = price * pout;
var fsbo = price * pout;
var hret = price * .02;
var others = price * .06;
var saves = others - hret;
document.getElementById("sellingprice").value = sellingprice.toFixed(2);
document.getElementById("hret").value = hret.toFixed(2);
document.getElementById("fsbo").value = fsbo.toFixed(2);
document.getElementById("others").value = others.toFixed(2);
document.getElementById("saves").value = saves.toFixed(2);
}
</script>
</body>
</html>希望这对:)有所帮助