assigning a item from a .json file to a variable in javascript

Assuming you've read your json file into a javascript JSON object (do you need help with that as well?)

var R1 = new Array();    for(var i= 0 ; i< myJSON.length; i++){   R1.push(myJSON[i].BID);}

[EDIT]

Your document.write is happening before you've done any reading.

Remove it.

put a console.log instead in your anonymous callback from your $.get();

Make it look like this:

$.get('data1.json', function (data) {    var parsedArr = JSON.parse(data),    for (i = 0; i < parsedArr.length; i++) {        R1.push(parsedArr[i].BID);    }    for(i=0; i< R1.length; i++)      console.log("item " + i + " = " + R1[i]);});

Also if your json file really looks like this:

[ { "BID" : "4569749", }, { "BID" : "466759", }, { "BID" : "4561149", }, ]

Then it needs to be fixed to remove the extraneous commas inside your objects. It should look like this:

[ { "BID" : "4569749" }, { "BID" : "466759" }, { "BID" : "4561149" } ]

I haven't tested this, but it looks like it should work to me.

var R1 = [];$.get('file.json', function (data) {    var parsedArr = JSON.parse(data),    i = 0, l = parsedArr.length;    for (i; i < l; i++) {        R1.push(parsedArr[i].BID);    }});

Getting the json file with ajax, then process it and assign to R1:

function ajaxGetJson(url, callback){    var xmlhttp = new XMLHttpRequest();    xmlhttp.onreadystatechange = function() {        if (xmlhttp.readyState == 4 && xmlhttp.status == 200) {            callback(eval(xmlhttp.responseText));        }    }    xmlhttp.open("GET", url, true);    xmlhttp.send();}var R1;ajaxGetJson('file.json', function(obj){   R1 = obj.map(function(item){ return item.BID });});

Some comments:

• I'm using eval instead of JSON.parse because your .json may not be in strict json format (as your example)

• As the question has tag html5, your browser for sure supports the .map method

Cheers, from La Paz, Bolivia