JERUSALEM, March 2 (Reuters) - Avi B. wanted to know if he could receive a warning via a text message on his cell phone of an impending rocket attack on southern Israel from the Gaza Strip.

Matan wondered whether the rockets will reach the Israeli coastal city of Ashdod, which so far has been out of range of salvoes from militant groups across the frontier, where an Israeli offensive has killed more than 100 Palestinians, including about 60 civilians.

Those were just some of the questions Israelis participating in an Internet chat on Sunday on Israel's popular YNet news Web site posed to Lieutenant-Colonel Ariella Ben-Avraham, a spokeswoman for the army's Home Command.

One Israeli civilian was killed by a rocket launched from Gaza on Wednesday. Two Israeli soldiers have been killed during the Gaza offensive.

Ben-Avraham advice was straightforward: the main early warning available was an alarm sounded over loudspeakers in southern Israeli towns -- "Colour Red" -- that would give them about 15 seconds to seek cover.

Ben-Avraham said people living in homes with special "safe" rooms of reinforced concrete should use them when rockets fly. Others should go into a room facing away from Gaza to the south.

Pedestrians and motorists on city streets should race to the closest building for cover, she said.

Her advice to motorists on the open road: "Upon hearing an alert ... you should pull over, get out of your car, lie down and protect your head with your hands," she wrote.

At least one chat participant was unimpressed by the advice.

"If Hamas is reading this, please inform us some weeks in advance so we can sell our apartment," said the message, signed simply "an Ashdod resident".

Palestinians in Gaza do not have an official air raid warning system but have become well versed in taking precautions when air strikes seem imminent. (Writing by Brenda Gazzar; Editing by Alison Williams)

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