顺时针打印矩阵

function printMatrix(matrix)
{
    // write code here
    var rows;
    var cols;
    var i,j;
    var result = [];
    if(matrix.length === 0 ){
        return result;
    }else{
//读取矩阵第一行的元素
        cols = matrix[0].length;
        if(cols > 0){
        i = 0;
        while(i < cols){
            result.push(matrix[0][i]);
            i++;
        }
        matrix.shift();
    }
    rows = matrix.length;
    //读取矩阵最后一列元素
    if(rows > 0){
        cols = matrix[0].length;
        j = 0;
        while(j < rows && cols != 0){
            result.push(matrix[j][cols-1]);
            matrix[j].pop();
            j++;
        }
    }else{
        return result;
    }
    rows = matrix.length;
    //读取最后一行的元素
    if(rows > 0){
        cols = matrix[0].length;
        j = cols-1;       
        while(j >= 0 && cols != 0){
           result.push(matrix[rows-1][j]);
            j--;
        }
       matrix.pop();
    }else{
        return result;
    }
    rows = matrix.length;
    //读取第一列的元素
    if(rows > 0){
        cols = matrix[0].length;
        i = rows - 1;
        while(i >= 0 && cols != 0){
            result.push(matrix[i][0]);
            matrix[i].shift();
            i--;
        }
    }else{
        return result;
    }
    return result.concat(printMatrix(matrix));
    }
}