|OK Cupid's message directs customers to use other browsers, like Internet Explorer, to access the site|
Dating website OKCupid has sought to deter users from accessing its site via browser Mozilla Firefox.
The site says the move was in response to new Mozilla chief executive Brendan Eich's previous opposition to gay marriage in the US state of California.
Users are directed to use other internet browsers, such as Chrome.
Mozilla said OKCupid had not contacted it to confirm facts, and that: "Mozilla supports equality for all, including marriage equality for LGBT couples."
Visitors to OKCupid's website using Mozilla's free Firefox browser see a message that reads: "Mozilla's new CEO, Brendan Eich, is an opponent of equal rights for gay couples.
"We would therefore prefer that our users not use Mozilla software to access OKCupid."
However, it is still possible to access OKCupid's site via Firefox, if users click through the message.
Ok Cupid is owned by media conglomerate IAC/InterActive Corp, which owns 50 brands across 40 countries.
These include other major dating sites, like Match.com, as well as news website the Daily Beast and web properties like Dictionary.com.
He is listed publicly as having donated to a campaign in support of California's Proposition 8 campaign in 2008, which had sought to ban gay marriage in the western US state.
Although it was initially passed, it was later overturned by the US Supreme Court in 2013.
After his appointment was announced, supporters of same-sex marriage in the US, including many Mozilla employees, expressed unease at the decision.
Mozilla's head of education, Christie Koehler, who is gay, wrote on her blog: "It's hard for me to think of a scenario where someone could donate to that campaign without feeling that queer folks are less deserving of basic rights."
However, she added that while she was personally disappointed, she said she did not think it would affect her work at Mozilla.
Mr Eich responded in a post, saying that he remained committed to openness in the work place and offering assurances that Mozilla would not change certain policies, like health insurance for the partners of gay employees.
"I am committed to ensuring that Mozilla is, and will remain, a place that includes and supports everyone, regardless of sexual orientation, gender identity, age, race, ethnicity, economic status, or religion," he wrote.