How to create json by JavaScript for loop

Question

I have array of select tag    lt select id  uniqueID  name  status  gt         lt option value  1  gt Present lt  option gt         lt option value  2  gt Absent lt  option gt    lt  select gt    and I want to create a json object having two fields  uniqueIDofSelect and optionValue  in JavaScript   I use getElementsByName  status   and I iterate on it   EDIT  I need out put like     selectID  2  OptionValue   2      selectID  4  optionvalue   1      and so on

User · Answer

If I want to create JavaScript Object from string generated by for loop then I would JSON to Object approach. I would generate JSON string by iterating for loop and then use any popular JavaScript Framework to evaluate JSON to Object.

I have used Prototype JavaScript Framework. I have two array with keys and values. I iterate through for loop and generate valid JSON string. I use evalJSON() function to convert JSON string to JavaScript object.

Here is example code. Tryout on your FireBug Console

var key = ["color", "size", "fabric"];
var value = ["Black", "XL", "Cotton"];

var json = "{ ";
for(var i = 0; i < key.length; i++) {
    (i + 1) == key.length ? json += "\"" + key[i] + "\" : \"" + value[i] + "\"" : json += "\"" + key[i] + "\" : \"" + value[i] + "\",";
}
json += " }";
var obj = json.evalJSON(true);
console.log(obj);

User · Answer

Your question is pretty hard to decode  but I ll try taking a stab at it   You say      I want to create a json object having two fields   uniqueIDofSelect and optionValue in javascript    And then you say      I need output like     selectID  2  optionValue   2      selectID  4  optionvalue   1       Well  this example output doesn t have the field named uniqueIDofSelect  it only has optionValue   Anyway  you are asking for array of objects     Then in the comment to michaels answer you say      It creates json object array  but I need only one json object    So you don t want an array of objects   What do you want then   Please make up your mind

User · Answer

From what I understand of your request  this should work    lt script gt      var status    document getElementsByID  uniqueID       this works too var status    document getElementsByName  status   0   var jsonArr        for  var i   0  i  lt  status options length  i          jsonArr push           id  status options i  text          optionValue  status options i  value            lt  script gt

User · Answer

If you want a single JavaScript object such as the following     uniqueIDofSelect   uniqueID   optionValue   2       where option 2   Absent   is the current selection  then the following code should produce it     var jsObj   null    var status   document getElementsByName  status   0     for  i   0  i  lt  status options length    i         if  options i  selected             jsObj     uniqueIDofSelect  status id  optionValue  options i  value            break               If you want an array of all such objects  not just the selected one   use michael s code but swap out status options i  text for status id   If you want a string that contains a JSON representation of the selected object  use this instead     var jsonStr         var status   document getElementsByName  status   0     for  i   0  i  lt  status options length    i         if  options i  selected             jsonStr                              uniqueIDofSelect                                status id                                                      optionValue                               options i  value                                         break

User · Answer

var sels     Here is your array of SELECTs var json         for var i   0  l   sels length  i  lt  l  i        json sels i  id    sels i  value

[javascript] How to create json by JavaScript for loop?

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