can't set value of form input javascript

Question

I assign document.getElementById("outcome").value to variable outcome. When I click the button, I want to set value of input that has id "outcome" to "Something".

But when I execute my code below, input form outcome was not set. Still, input form outcome is nothing happened.

function throwDice() {

    var point=document.getElementById("point").value;
    var outcome=document.getElementById("outcome").value;
    outcome=Somthing;
}

After that I modify my code right this.

function throwDice() {

    var point=document.getElementById("point").value;

    document.getElementById("outcome").value="Something";
}

All I do is that remove assigning variable outcome and assign "Something" to document.getElementById("outcome").value directly. In this case value of input form outcome is "Something".

My question is why outcome="Something" isn't operate.

Variables aren't references to properties.

Bergi
– Bergi

2017-04-09 23:06:59 +00:00
Commented Apr 9, 2017 at 23:06 — Bergi
– Bergi, Commented Apr 9, 2017 at 23:06

cнŝdk · Accepted Answer · 2017-04-09 21:46:55Z

2

Situation:

In your first code, you are only overwriting outcome variable value with "Something" instead of writing it into element with id outcome, so if you write:

Explanation:

Here you declared outcome variable and set its value to the value of your input:

var outcome=document.getElementById("outcome").value;

And here in this line you are resetting outcome variable to "Something"

outcome=Somthing;

So in this case outcome variable was just holding the input value, then you changed it to "Something".

So to answer your question: why outcome="Something" isn't operate?, it's because outcome doesn't refer the input element value, but only holds its value.

In other words:

So in your first code you were just doing something like this:

var outcome = 5;     //outcome here is 5
outcome = "Something";    //outcome is changed to "Something"

In JavaScript variables are loosly typed that's why you see this behaviour, you can take a look at Understanding Loose Typing in JavaScript for further reading.

edited Apr 9, 2017 at 21:46

answered Apr 9, 2017 at 21:41

cнŝdk

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2 Comments

nuroo cocoa Over a year ago

although my terrible English, You answer to my question. Thank you for your rapid answer. I understand my mistake.

cнŝdk Over a year ago

@nuroococoa if it helps you can you please accept my answer. Thank you

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