Knowledge Walls
John Peter
Pune, Maharashtra, India
How to get first key of json object in javascript with Example.
for loop runs one time to get first key.

for(var firstKey in data);

Using firstKey taking the from data object. Thus data[firstKey] returns the first value from an array object.
FirstKey and firstValue of the JSON
var data = {};
    data.rno = 1001;

for(firstKey in data);

document.write(firstKey+"<br />");
document.write(data[firstKey]+"<br />");
Demo & Output 
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