I have tried to get json response from public salesforce API 'https://na1.salesforce.com/services/data/'. When I use HTTP/REST tool its working fine and return string as json. But when I am tring to call public API through jQuery AJAX request and giving following error:

"Cross-Origin Request Blocked: The Same Origin Policy disallows reading the remote resource at https://na1.salesforce.com/services/data/. (Reason: CORS header 'Access-Control-Allow-Origin' missing)."

Please provide the solution how can I call API from simple HTML page using AJAX request.

I am new in Salesforce. Today I have downloaded Data Loader to check import functionality from desktop. But when I am trying to get login via Data Loader, it's give error. 'Error log in to Salesforce' whereas I can login into salesforce in browser with same credential.

Will you please help me out this problem?

I am new in Salesforce. Today I have downloaded Data Loader to check import functionality from desktop. But when I am trying to get login via Data Loader, it's give error. 'Error log in to Salesforce' whereas I can login into salesforce in browser with same credential.

Will you please help me out this problem?