Posting the value of an html textarea to CRM's Multi Line field

Posting the value of an html textarea to CRM's Multi Line field

 Hi all
 
 I have an html form on a webpage. Im using cURL PHP to get the value of a textarea field and insert it into a Multi Line field in the CRM.
 
 Ive realised I cant have line breaks in the textarea field becuase it breaks the json.
 
 Id like to be able to POST the line breaks etc (which the CRM's Multi Line field does support) in the json.
 
 How can this be done?
 
 Thanks