isRelative(url)

function isRelative(url){
    if (/^(((file:|https?:)?\/\/?)?[a-z0-9][a-z0-9-]*(\.([a-z0-9-]*[a-z0-9]))+(:\d+)?|((file:|https?:)?\/\/\/?[a-z0-9][a-z0-9-]*(\.([a-z0-9-]*[a-z0-9]))*))+(:\d+)?/i.test(url)) return false;
	return true;
    
    if(!url) return true;
    if(/^\/\/[^\/]+\.[^\/]/.test(url)) return false;
    if(/^\/\/\/[^\/]+/.test(url)) return false;
    if(/^https?:\/\//.test(url)) return false;
    var dot = url.indexOf('.'),
        slash = url.indexOf('/');
    if(dot > -1 && ( dot < slash || slash == -1)) return false;
    return true;
}

var testData = [
    {relative: true,url: "/path/to/file.ext"},
    {relative: true,url: "path/to/file.ext"},
    {relative: true,url: "file"},
    {relative: true,url: "/path"},
    {relative: true,url: "#target"},
    {relative: true,url: "?query=string"},
    {relative: false,url: "http://www.google.com/path/to/file.ext"},
    {relative: false,url: "//www.google.com/path/to/file.ext"},
    {relative: false,url: "www.google.com/path/to/file.ext"},
    {relative: false,url: "www.google.com"},
    {relative: false,url: "google.com/path/to/file.ext"},
    {relative: false,url: "https://www.google.com/path/to/file.ext"},
    {relative: false,url: "///what-is-this?"},
    {relative: false,url: "file:///what-is-this?"},
    {relative: false,url: "http://one"}
];


console.log("\n%cRunning tests...", "font-weight:bold;font-size:1.2rem");
var successCount = 0,
    failureCount = 0,
    failures = [];
for(var i=0; i < testData.length; i++){
    if(isRelative(testData[i].url) == testData[i].relative){
        successCount++;
    }else{
        failures.push({
            index: i,
            result: isRelative(testData[i].url),
            data: testData[i]
        });
        failureCount++;
    }
}
console.log(
    "Tests complete: " + 
    failureCount + " failed %o, " +
    successCount + " succeeded, " + 
    "total: " + testData.length,
    failures
)