Javascript JQuery：更改其他输入字段的值时更改值
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JQuery: Change value when value of other input field is changed
提问by Anujan
I want to change the value of an input field whenever the value of another one is changed.
每当更改另一个输入字段的值时，我想更改输入字段的值。
I've tried for a while and I can't seem to get it to work
我已经尝试了一段时间，但似乎无法正常工作
<input class="span4 input-big" id="dare_price" name="price" size="30" type="text" onChange="updatePrice()" />
<input class="span4 input-big" id="total_price_amount" readonly="readonly" value=""/>?
function updatePrice() {
var price = $("#dare_price").val();
var total = (price + 1) * 1.05;
$("$total_price_amount").val(total);
}?
采纳答案by Robin Maben
$("#dare_price").change(function(){
var total = Number($this).val()) + ...;
$('#total_price').val(total);
});
If you programatically change the values, you need to pipeline them through your method -
如果您以编程方式更改值，则需要通过您的方法将它们流水线化 -
function changePrice(value){
$('#dare_price').val(value);
$('#dare_price').trigger('change');
}
Updated DEMOfor this event-driven approach.
为这种事件驱动的方法更新了 DEMO。
回答by OACDesigns
A couple of things.
几件事。
Firstly I'd use the newest version of jQuery if I were you. We're on 1.8 now.
I'd also use "keyup" as the event trigger as well as "change". it's just more usable in my opinion. I like to bind events using jQuery also. See http://api.jquery.com/on/
there were some errors in your code. Note the
$("$total_price_amount")part was throwing an errorIf you want to only show a set number of decimal point, use
.toFixed(). But note that this will return a string.input values from text boxes are type
string, so to do mathematical calculations with them you need to parse them to anintor afloat
首先，如果我是你，我会使用最新版本的 jQuery。我们现在是 1.8。
我还会使用“keyup”作为事件触发器以及“change”。在我看来它更有用。我也喜欢使用 jQuery 绑定事件。见http://api.jquery.com/on/
您的代码中有一些错误。请注意该
$("$total_price_amount")部件引发错误如果您只想显示一组小数点，请使用
.toFixed(). 但请注意，这将返回一个字符串。文本框中的输入值是 type
string，因此要对它们进行数学计算，您需要将它们解析为 anint或 afloat
Here's my updated JSFiddle
这是我更新的 JSFiddle
http://jsfiddle.net/DigitalBiscuits/QWSQp/71/
http://jsfiddle.net/DigitalBiscuits/QWSQp/71/
And the actual code I used
我使用的实际代码
$(document).ready(function()
{
function updatePrice()
{
var price = parseFloat($("#dare_price").val());
var total = (price + 1) * 1.05;
var total = total.toFixed(2);
$("#total_price_amount").val(total);
}
$(document).on("change, keyup", "#dare_price", updatePrice);
});
notethat I removed the onChange="updatePrice()"part from the HTML as it's no longer needed.
请注意，我onChange="updatePrice()"从 HTML 中删除了该部分，因为它不再需要。
Hope this helps you.
希望这对你有帮助。
回答by Mark Pieszak - Trilon.io
Just to be safe you should parseFloat()your price. Also, before doing any of this you should make sure it is even a number to begin with! Otherwise you'll get NaN
为了安全起见，你应该parseFloat()你的价格。此外，在做任何这些之前，你应该确保它是一个数字！否则你会得到NaN
function updatePrice() {
var price = $("#dare_price").val();
var total = (parseFloat(price) + 1) * 1.05;
console.log(total);
// Other big problem was the $total_price_amount typo that should of had # instead
$("#total_price_amount").val(total);
}?
回答by rosscj2533
Just looks like a typo
只是看起来像一个错字
$("$total_price_amount").val(total);
Should be
应该
$("#total_price_amount").val(total);
Use the '#' to get the id
使用“#”获取id
回答by David 10K
Here an example with the change event. You can use events like keydown or -up, whatever suits to your purposes.(The live-method is used for elements created during runtime.)
这是更改事件的示例。您可以使用 keydown 或 -up 之类的事件，任何适合您的目的。（live-method 用于在运行时创建的元素。）
$('#first').live("change", (function(){
$('#idofinputfield').val('mynewvalue');
}))
