var tablinks= document.getElementsByClassName("tab-links");
var tabcontents= document.getElementsByClassName("tab-contents");
function openTab(tabname){
    for(tablink of tablinks ){
        tablink.classList.remove("active-link");
    }
    for( tabcontent of  tabcontents ){
        tabcontent.classList.remove("active-tab");
        event.currentTarget.classList.add("active-link");
        document.getElementById(tabname).classList.add("active-tab")
    }
}