Javascipt and jQuery for adding multiple selection of table rows

multiple_table_row_selection.js

$(document).ready(function(){
  //put all the table rows in a variable after page load to pass in to RowClick
  var trs = $('#main-table tr')
  //bind the click handler to all the table rows
  $('tr').on('click', function(){
      //call the RowClick function on click event
      RowClick($(this),false,trs)
  })
})

//declare variable to store the most recently clicked row
var lastSelectedRow;

// disable text selection
document.onselectstart = function() {
    return false;
}

function RowClick(currentrow, lock, rows) {
    //if control is held down, toggle the row
    if (window.event.ctrlKey) {
        toggleRow(currentrow);
    }
    
    //if there are no buttons held down...
    if (window.event.button === 0) {
        
        //if neither control or shift are held down...
        if (!window.event.ctrlKey && !window.event.shiftKey) {
            //clear selection
            clearAll(rows);
            //toggle clicked row
            toggleRow(currentrow);
        }
        
        //if shift is held down...
        if (window.event.shiftKey) {
            //pass the indexes of the last selected row and currently selected row along with all rows
            selectRowsBetweenIndexes([lastSelectedRow.index(), currentrow.index()], rows)
        }
    }
}

function toggleRow(row) {
    //if the row is not the header row...
    if (!row.hasClass('header-row')){
        //if the row is selected...
        if (row.hasClass('selected')){
            //deselect it
            row.removeClass('selected')
        }
        else{
            //otherwise, select it
            row.addClass('selected')
        }
        //reassign the most recently selected row
        lastSelectedRow = row;
    }
}

function selectRowsBetweenIndexes(indexes,rows) {
    //sort the indexes in ascending order
    indexes.sort(function(a, b) {
        return a - b;
    });
    
    //for every row starting at the first index, until the second index...
    for (var i = indexes[0]; i <= indexes[1]; i++) {
        //select the row
        $(rows[i+1]).addClass('selected');
    }
}

function clearAll(rows) {
    //for all rows...
    for (var i = 0; i < rows.length; i++) {
        //deselect each row
        $(rows[i]).removeClass("selected");
    }
}