Is there a way to pass a WebElement to javascript in Robot?

Is there a way to pass a WebElement to javascript in Robot? My script:

${el} =    Get Webelement    ${locator}
Execute Javascript    ${el}.checked = true;    #not sure how to approach this bit

I cannot use document.getElementById("whatever") as in some certain cases there's no ID used but custom locators.

Many thanks for your help!

So yes, I've got the solution by combination of above:

Select Checkbox
    [Arguments]    ${locator}    ${timeout}=${global_timeout}
    ${tempId} =    Generate Random String    8
    Wait Until Page Contains Element    locator=${locator}    timeout=${timeout}
    ${origId} =    Get Element Attribute    ${locator}@id
    Assign Id To Element    locator=${locator}    id=${tempId}
    Execute Javascript    document.getElementById("${tempId}").checked = true;
    ${locator} =    Replace String    string=${locator}    search_for=${origId}    replace_with=${tempId}
    Assign Id To Element    locator=${locator}    id=${origId}

Unselect Checkbox
    [Arguments]    ${locator}    ${timeout}=${global_timeout}
    ${tempId} =    Generate Random String    8
    Wait Until Page Contains Element    locator=${locator}    timeout=${timeout}
    ${origId} =    Get Element Attribute    ${locator}@id
    Assign Id To Element    locator=${locator}    id=${tempId}
    Execute Javascript    document.getElementById("${tempId}").checked = false;
    ${locator} =    Replace String    string=${locator}    search_for=${origId}    replace_with=${tempId}
    Assign Id To Element    locator=${locator}    id=${origId}

Checkbox Should Be Selected
    [Arguments]    ${locator}    ${timeout}=${global_timeout}
    Wait Until Page Contains Element    locator=${locator}    timeout=${timeout}
    ${el} =    Get Webelement    ${locator}
    Should Be True    ${el.is_selected()}

Checkbox Should Not Be Selected
    [Arguments]    ${locator}    ${timeout}=${global_timeout}
    Wait Until Page Contains Element    locator=${locator}    timeout=${timeout}
    ${el} =    Get Webelement    ${locator}
    Should Not Be True    ${el.is_selected()}