如何针对不同条件将日期设置为 ISOString

Question

I'm trying to set a date in future based on different condition and then convert the date into string using the ISOString method. This is an example of the code;

<input type="text" name="unknown" id="dater" />

<p id="show"></p>

<button id="but">Show Date</button>

Having the script:

var text = document.getElementById("dater");
var date = new Date();
var n = date.setDate(date.getDate() + 12);
var x = date.toISOString()
var y = x.slice(0, -14);

document.getElementById("show").innerHTML = y;

Result:

2018-05-27

The output is based on today's date which is "2018-05-15". Now I want to set different date based on different conditions. I tried the following:

var pres = document.getElementById("but").addEventListener("click", now)

function now() {

var text = document.getElementById("dater");
var date = new Date();
var n = date.setDate(date.getDate() + 12);
var x = date.toISOString()
var y = x.slice(0, -14);

if(text.value == 5) { n = date.setDate(date.getDate() + 15)

 } else if(text.value == 12) { n = date.setDate(date.getDate() + 22)

} else { n = date.setDate(date.getDate() + 3) }

document.getElementById("show").innerHTML = y;

 }

if i input 5, 12 or 3 in the text field, nothing happens when I click the button. It just returns the same date "2018-05-27". However, if i say

document.getElementById("show").innerHTML = n; 

or

document.getElementById("show").innerHTML = n.toISOString();

It returns the date in milliseconds.

Answer 1

I think this code will help you. you are not converting your variable in to Date object.

    window.onload = function () {
        var pres = document.getElementById("but").addEventListener("click", now);
    }

    function now() {

        var text = document.getElementById("dater");
        var date = new Date();
        var n = date.setDate(date.getDate() + 12);
        var x = date.toISOString()
        var y = x.slice(0, -14);

        if (text.value == 5) {
            n = date.setDate(date.getDate() + 15)

        } else if (text.value == 12) {
            n = date.setDate(date.getDate() + 22)

        } else { n = date.setDate(date.getDate() + 3) }

        document.getElementById("show").innerHTML = new Date(n).toISOString();

    }