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@daolf
Last active July 18, 2024 15:33
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https://jennamolby.com/how-to-use-cookies-to-capture-url-parameters/
let YOUR_DOMAIN = "YOUR_DOMAIN.TLD" // ex: scrapingbee.com
function getParameterByName(name) {
name = name.replace(/[\[]/, "\\[").replace(/[\]]/, "\\]");
var regex = new RegExp("[\\?&]" + name + "=([^&#]*)"),
results = regex.exec(location.search);
return results === null ? "" : decodeURIComponent(results[1].replace(/\+/g, " "));
}
// Give the URL parameters variable names
var utm_source = getParameterByName('utm_source');
var utm_medium = getParameterByName('utm_medium');
var utm_campaign = getParameterByName('utm_campaign');
var utm_term = getParameterByName('utm_term');
var now = new Date();
now.setMonth( now.getMonth() + 1 );
function getCookie(cname) {
var name = cname + "=";
var decodedCookie = decodeURIComponent(document.cookie);
var ca = decodedCookie.split(';');
for(var i = 0; i <ca.length; i++) {
var c = ca[i];
while (c.charAt(0) == ' ') {
c = c.substring(1);
}
if (c.indexOf(name) == 0) {
return c.substring(name.length, c.length);
}
}
return "";
}
// Set the cookies
if(utm_source != "" && getCookie("utm_source") == "") {
document.cookie = `utm_source=${utm_source}; domain=${YOUR_DOMAIN}; expires="${now.toUTCString()}"`
}
if(utm_medium != "" && getCookie("utm_medium") == "") {
document.cookie = `utm_medium=${utm_medium}; domain=${YOUR_DOMAIN}; expires="${now.toUTCString()}"`
}
if(utm_campaign != "" && getCookie("utm_campaign") == "") {
document.cookie = `utm_campaign=${utm_campaign}; domain=${YOUR_DOMAIN}; expires="${now.toUTCString()}"`
}
if(utm_term != "" && getCookie("utm_term") == "") {
document.cookie = `utm_term=${utm_term}; domain=${YOUR_DOMAIN}; expires="${now.toUTCString()}"`
}
if(document.referrer != "" && getCookie("referrer") == "") {
document.cookie = `referrer=${document.referrer}; domain=${YOUR_DOMAIN}; expires="${now.toUTCString()}"`
}
// Set the cookies
var utm_journey = getCookie("utm_journey");
var current_relative_path = location.href.replace(location.origin,'');
if (utm_journey != "") {
old_journey = atob(utm_journey)
new_journey = `${old_journey} - ${current_relative_path}`
document.cookie = `utm_journey=${btoa(new_journey)}; domain=${YOUR_DOMAIN}; path=/;`
} else {
document.cookie = `utm_journey=${btoa(current_relative_path)}; domain=${YOUR_DOMAIN}; expires="${now.toUTCString()}; path=/;`
}
@joostvanhoof
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joostvanhoof commented Sep 7, 2020

For some reason, the Expires value was always set to Session instead of one month from now. I tried different things but it didn't work, so ended up using something that I already use, see below.

  • Function to set cookie
  • Added SameSite attribute with fallback for older browsers (see code comments for links with info)

Feel free to update the Gist with this!

function getParameterByName(name) {
	name = name.replace(/[\[]/, "\\[").replace(/[\]]/, "\\]");
	var regex = new RegExp("[\\?&]" + name + "=([^&#]*)");
	var results = regex.exec(location.search);
	return results === null ? "" : decodeURIComponent(results[1].replace(/\+/g, " "));
}

// Give the URL parameters variable names
var utm_source = getParameterByName('utm_source');
var utm_medium = getParameterByName('utm_medium');
var utm_campaign = getParameterByName('utm_campaign');

function getCookie(cname) {
    var name = cname + "=";
    var decodedCookie = decodeURIComponent(document.cookie);
    var ca = decodedCookie.split(';');
    for(var i = 0; i <ca.length; i++) {
        var c = ca[i];
        while (c.charAt(0) == ' ') {
            c = c.substring(1);
        }
        if (c.indexOf(name) == 0) {
            return c.substring(name.length, c.length);
        }
    }
    return "";
}

function setCookie(cname, cvalue) {
    const d = new Date();
    d.setTime(d.getTime() + (30 * 24 * 60 * 60 * 1000)); // 30 = number of days
    const expires = `expires=${d.toUTCString()}`;
    // Using the new SameSite attribute: https://web.dev/samesite-cookie-recipes/
    document.cookie = `${cname}=${cvalue};${expires};path=/;SameSite=Strict`;
    // Fallback for legacy browsers: https://web.dev/samesite-cookie-recipes/
    document.cookie = `${cname}=${cvalue};${expires};path=/;Secure`;
}
 
// Set the cookies
if(utm_source != "" && getCookie("utm_source") == "") {
    setCookie('utm_source', utm_source);
}
if(utm_medium != "" && getCookie("utm_medium") == "") {
	setCookie('utm_medium', utm_medium);
}
if(utm_campaign != "" && getCookie("utm_campaign") == "") {
	setCookie('utm_campaign', utm_campaign);
}
if(document.referrer != "" && getCookie("referrer") ==  "") {
    setCookie('referrer', document.referrer);
}

@daolf
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daolf commented Sep 7, 2020

This is nice! Thank you very much.

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