hmm first time using this site, there are still lots room to improve I think.

I'm using mac currently and really sleepy now so didn't bother to get the nginx installed.

just gonna post the js code with comments here :D

assuming every single cell is in a div with cell as class name and id from 1 to 9.

execute the following function when onload:

function changeColor () {

for (var j = 1; j < 10; j++) {    // reset all the divs before changing color.

var colorDiv = document.getElementById(j);

if (colorDiv.className != "cell") {

colorDiv.className = "cell";

}

}

var randomDiv = document.getElementsByClassName("cell"); // get all the divs.

var i = Math.floor(Math.random() * 9);  // get a random div from 1 to 9.

var k = Math.floor(Math.random() * 10);  //get a random color.

if (k <= 3) {

randomDiv[i].className = "red";

console.log("格子" + (i + 1) + "变成了红色");

}else if (k <=6) {

randomDiv[i].className = "blue";

console.log("格子" + (i + 1) + "变成了蓝色");

}else {

randomDiv[i].className = "green";

console.log("格子" + (i + 1) + "变成了绿色");

}

setTimeout(changeColor, 1000);

}