js code to return the color of the circular gradient using increasing numbers_javascript skills

The function is as follows:

Copy code The code is as follows:

function gCL(i){
var f=parseInt((i )/5);
i=i %5;
switch(f){
case 0:return "#" cS2(255-i*51) cS2 (i*51) "00";
case 1:return "#00" cS2(255-i*51) cS2(i*51);
case 2:return "#" cS2(i*51 ) "00" cS2(255-i*51);
}
}
function cS2(i) {
var s=i.toString(16);
return ("00 " s).substr(s.length);
}

Using gCL, you can use increasing numbers to return the gradient color from red to green to blue. The gradient effect is as follows, a total of 15 colors, cyclic gradient:

For example, in the following application, use this function to gradient the background color of a hyperlink:

<a id="a" onmouseover="cancel=0;colorful()" onmouseout="cancel=1;" href="http://www.jb51.net">Homepage</a>
[Ctrl A Select all Note: If you need to introduce external Js, you need to refresh to execute it

]
This function can be modified Produce more detailed color changes, interested friends can try it.