Create an script in javascript to convert an HTML Table to JSON (without jquery)

I need to convert several tables, that I have in string format:
see sample attached

And I need a JSON format like this one:
[
{
"Company": "Citi",
"2017/18*": "USD 748m",
"Last Revised": "1 November 2017"
},
{
"Company": "CLSA",
"2017/18*": "USD 750m",
"Last Revised": "5 January 2018"
},
{
"Company": "Credit Suisse",
"2017/18*": "USD 712m",
"Last Revised": "1 November 2017"
},
{
"Company": "Deutsche Bank",
"2017/18*": "USD 814m",
"Last Revised": "1 November 2017"
},
{
"Company": "Evans & Partners",
"2017/18*": "USD 763m",
"Last Revised": "17 January 2018"
},
{
"Company": "JP Morgan",
"2017/18*": "USD 758m",
"Last Revised": "22 November 2017"
},
{
"Company": "Macquarie",
"2017/18*": "USD 792m",
"Last Revised": "24 January 2018"
},
{
"Company": "Morgans",
"2017/18*": "USD 792m",
"Last Revised": "24 January 2018"
}
]