The example in this article describes the method of realizing rainbow text effect in JavaScript. Share it with everyone for your reference. The details are as follows:
<HTML>
<HEAD>
<TITLE>Rainbow Text</TITLE>
<SCRIPT LANGUAGE="JavaScript">
<!-- Begin hide from old browsers
function createHexArray(n)
{
this.length = n;
for (var i = 1; i <= n; i++)
this[i] = i - 1;
this[11] = "A";
this[12] = "B";
this[13] = "C";
this[14] = "D";
this[15] = "E";
this[16] = "F";
return this;
}
hx = new createHexArray(16);
function convertToHex(x)
{
if (x < 17)
x = 16;
var high = x / 16;
var s = high+"";
s = s.substring(0, 2);
high = parseInt(s, 10);
var left = hx[high + 1];
var low = x - high * 16;
if (low < 1)
low = 1;
s = low + "";
s = s.substring(0, 2);
low = parseInt(s, 10);
var right = hx[low + 1];
var string = left + "" + right;
return string;
}
function makeRainbow(text)
{
text = text.substring(0, text.length);
color_d1 = 255;
mul = color_d1 / text.length;
for(var i = 0; i < text.length; i++) {
color_d1 = 255*Math.sin(i / (text.length / 3));
color_h1 = convertToHex(color_d1);
color_d2 = mul * i;
color_h2 = convertToHex(color_d2);
k = text.length;
j = k - i;
if (j < 0)
j = 0;
color_d3 = mul * j;
color_h3 = convertToHex(color_d3);
document.write("<FONT COLOR=\"#" + color_h3 + color_h1 +
color_h2 + "\">" + text.substring(i, i + 1) + "</FONT>");
}
}
// End hide from old browsers -->
</script>
</HEAD>
<body bgcolor="#FFFFCC">
<center>
<strong>
<font size=6>
<script>
<!--
// change to your own text ...
makeRainbow("Welcome to Boulder City Nevada");
document.write("<br>");
makeRainbow("The best dam city in the USA");
// -->
</script>
</font>
</strong>
</center>
</body>
</html>I hope this article will be helpful to everyone’s JavaScript programming design.
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