"For there is one God, and one mediator between God and men, the man Christ Jesus, who gave himself as a ransom for all; the testimony in its own times" (1 Timothy 2:5 & 6)
There are not, as "On Islam" suggests, different prayers for the same God, as "Allah" is an imposter, both denying the deity of Jesus Christ, and His crucifixion.
[It is evident from the Quran that all the communities that existed before the arrival of Prophet Muhammad (peace be upon him) were taught by their respective prophets to regularly pray to Allah Almighty alone. But we have no clear description of the form of their prayer.
See the following verses from the Quran that say how some of the prophets before Prophet Muhammad had received the command to establish Prayer.
Prophet Abraham (peace be upon him) asked Allah's support and blessings for him as well as for his progeny in these words:]
More of the spiritual fornication with a false god at "On Islam"
Who Jesus Christ is:
"For God so loved the world, that he gave his one and only Son, that whoever believes in him should not perish, but have eternal life." (John 3:16)
What "Allah" denies:
"O followers of the Book! do not exceed the limits in your religion, and do not speak (lies) against Allah, but (speak) the truth; the Messiah, Isa son of Marium is only an apostle of Allah and His Word which He communicated to Marium and a spirit from Him; believe therefore in Allah and His apostles, and say not, Three. Desist, it is better for you; Allah is only one God; far be It from His glory that He should have a son, whatever is in the heavens and whatever is in the earth is His, and Allah is sufficient for a Protector."
(Sura 4:171, blasphemous Koran)