jQuery的计算问题 [英] jquery calculation question

问题描述

我有此代码:

<div>
    <input id="number" type="text" />

    <select id="Selection" name="D1"> 
    <option>Plus 1</option>
    <option>Minus 1</option>
    </select>

    <input id="result" type="text" />
    </div>

如何基于使用jQuery从选择控件中选择的值来计算输入到输入数字"中的任何数字? 例如，我想在输入数字"中输入5，如果我选择加号1"，则在数字上加1，并在结果"输入中显示结果.如果选择减1"，则将进行减法并显示新结果. 谢谢.

How could I calculate any number entered into the input "number" based on the value chosen from the select control using jQuery? For example I would like to enter 5 in the input "number" and if I choose "Plus 1" then add 1 to the number and show the result in the "result" input. If I choose "Minus 1" then I will do a substraction and show the new result. thank you.

推荐答案

您可以这样做:

$('#Selection').change(calc); //update result when changing the number
$("#number").keyup(calc);     //update result when select changes

function calc() {
  $('#result').val(
    parseInt($('#number').val(), 10) + parseInt($("#Selection").val(), 10)
  );
}

在此处尝试，重要的部分是

Give it a try here, the important part is the parseInt() your input (you should also add a numbers-only filter, etc.) Otherwise .val() from either input is a string, think of it this way:

• 1 + 1 == 2
• "1" + "1" = "11"

• 1 + 1 == 2
• "1" + "1" = "11"

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