JS change input value

Question

My problem is: I have two input boxes one for a code and one for a price:

<input class="style" name="code" id="code" type="text">
<input class="style" name="price" id= "price" type="text" value="&euro; 15,00" readonly="readonly">

Now i want to change the price by code (like a check from a code array [code1][code2]. result to code1 = price/2 and code2 = price/4 ) This i want to check by a script in real time or befor the post (on submit). This this possible when yes how? Or is there another better way to do this ?

I have:

while(true) 
{
    var code = document.getElementById("code").value;

    var codes = new Array("promo1", "promo2");

    for (var i=0; i<codes.length; i++) {

        if (codes[i] == code) {
            document.getElementById("price").value = "5";
        }       
    }
}

and my input fields are obviously in a form-field but the value doesnt change, but why ? I dont have to change in real time it would be ok if the post sends the new value...any solutions/better ideas/hints ? I know there is JQuery a better approach but it shouldn't be a problem with js.

fiddle link:
jsfiddle.net/vicR/4Mtbr

Daniel Varab · Accepted Answer · 2013-09-04 11:54:13Z

2

This can be obtained easily in many ways, specially if one takes use of libraries or frameworks, but with pure javascript it should be done as so:

while(true) {
 var code = document.getElementById("code").value
 //now check for valid code in some sort of map or array
 //REMEMBER javascript supports string indexed arrays such as arr["#45"]
 if(code == validatorFunctionOrCode) { //obviously pseudo
  document.getElementById("price").value = "your corresponding price to the code"
 }
}

This is all checked dynamically and before you hit the submit button.

With this said I would strongly recommend Angular.js since it supports databinding (example - databinding )

answered Sep 4, 2013 at 11:54

Daniel Varab

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4 Comments

vicR Over a year ago

is it okay to just implement the script into the header or is into an external .js file better (elegant)?

vicR Over a year ago

hmm.. i cannot get it to work. im kind of a js newbie. i'm having my conditions and implement it into my body. but no changes at all

vicR Over a year ago

i meant header. sorry.

Daniel Varab Over a year ago

1. Generally one it's more elegant to have the script in a different file. But when websites launch their sites they tend to "minimize" their html, css and js in a huge file so that the client doesn't hafto make multiple requests to the backend. 2. Could you give me a code dump on fiddle or such? it's easier to review.

long.luc · Accepted Answer · 2013-09-04 11:41:22Z

1

It is done with some jQuery code:

$('#form').submit(function() {
    $('#price').val(value_you_want_to_change);
});

answered Sep 4, 2013 at 11:41

long.luc

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2 Comments

vicR Over a year ago

this should change the value to value_you_want_to_change after submit or?!

long.luc Over a year ago

the value changed before submit

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