SOURCE

function getQueryVariable(query, variable){
    // var query = window.location.search.substring(1);
    var vars = query.split("&");
    for (var i=0;i<vars.length;i++) {
        var pair = vars[i].split("=");
        if(pair[0] == variable){
            // return pair[1];
            return vars[i].substring(`${variable}=`.length)
        }
    }
    return(false);
}

let query = 'id=1a==&img=image.png'

let id = getQueryVariable(query, 'id')

console.log('id => ', id)