Changing column/row numbers into a character count (JavaScript)

Right now, I have two numbers, a row number and a column number for a textarea.开发者_StackOverflow I need to translate that to the number of characters from the beginning of the textarea.

Example:

Row 5, character 6 should translate to 108 (The cursor is right after ornare before the period) if I have:

Lorem ipsum dolor sit amet, 
consectetur adipiscing elit. 
Suspendisse scelerisque 
sem in leo venenatis 
ornare. Aenean non
diam eget nisl 
molestie mattis. 

Any ideas how to calculate this via JavaScript?

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Here you go:

var area = document.getElementById("txtAreaID");
var rows = area.value.split(/\n/);

var getTotal = function(row, col){
    var tot = 0;
    var i;
    for (i=0; i<(row-1); i++){
        tot+=rows[i].length;
    };
    tot+=col;
    return tot;
};

alert(getTotal(5,6));

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var character_count = textarea.value.split(/\n/).slice(0,4).join('').length + 6;