JS examples of adding and removing thousandths_javascript skills

Copy code The code is as follows:

function commafyback(num)
{
var x = num.split(',');
return parseFloat(x.join(""));
}
function commafy(num)
{
num = num.toFixed(2 ) "";
var re=/(-?/d )(/d{3})/
while(re.test(num)){
num=num.replace(re," $1,$2");
}
return num;
}