如何检查Referrer URL是否有URL参数？

Question

I'd like to check if my Referrer URL has parameters in it. Because based on this I'd like to change the url of a button to a different page.

What I have now:

var referrer = document.referrer;
var referrerparams = referrer.search;

if (referrerparams) {
 > 'script to change urlbutton.href'
}

So I thought i could use both document.referrer and window.location.search, to see if the referrer URL has parameters in it. Independently these two work fine, but not together. I get the following in console: ƒ search() { [native code] } .

Does anyoneone know how to check if the Referrer URL has parameters? It doesn't even matter what parameters, just if they exit.

Answer 1

You can create a URL object from the referrer and check its search property.

const referrerQueryParamStr = new URL(document.referrer).search

if (referrerQueryParamStr) {
    // change urlbutton.href
}

If you want the individual key-value pairs in an easy-to-use format, you can use the searchParams property instead:

const referrerQueryParams = new URL(document.referrer).searchParams

for (const [key, val] of referrerQueryParams) {
    console.log({ key, val })
}

---

I get the following in console: ƒ search() { [native code] } .

This is because document.referrer is just a string before you convert it. What you're logging is actually the String#search function.

typeof document.referrer // string
typeof document.referrer.search // function
document.referrer.search === String.prototype.search // true