javasCript fAqs

Rainbow Links

Would you like to add a little flair to your pages? If so, this tutorial will show you how to make your page links automatically radiate rainbow colors.

This script is very easy to use. All you have to do is to add the script to the <head>...</head> tag pair in your HTML source code or save it as a javascript file and link to it on all of the pages you want it to work on.

One good thing about this script is that it can also be used with other text like paragrapghs and titles (pass your cursor over this paragraph to see this effect). Simply add 'onmouseover="doRainbow();"' and 'onmouseout="stopRainbow();"' to the target tags.

The Script

Highlight The Source Code Below

<script language="javascript">
<!--
/************************************************************************/
/* Rainbow Links Version 1.02 (2001.7.2)                                 */
/*                                                                      */
/* Copyright (C) 1999-2001 TAKANASHI Mizuki                             */
/* takanasi@hamal.freemail.ne.jp                                        */
/*----------------------------------------------------------------------*/
/* Read it somehow even if my English text is a little wrong! ;-)       */
/*                                                                      */
/* Usage:                                                               */
/*  Insert '<script src="rainbow.js"></script>' into the BODY section,  */
/*  right after the BODY tag itself, before anything else.              */
/*  You don't need to add "onMouseover" and "onMouseout" attributes!!   */
/*                                                                      */
/*  If you'd like to add effect to other texts(not link texts), then    */
/*  add 'onmouseover="doRainbow(this);"' and                            */
/*  'onmouseout="stopRainbow();"' to the target tags.                   */
/*                                                                      */
/* This Script works with IE4,Netscape6,Mozilla browser and above only, */
/* but no error occurs on other browsers.                               */
/************************************************************************/


////////////////////////////////////////////////////////////////////
// Setting

var rate = 20;  // Increase amount(The degree of the transmutation)


////////////////////////////////////////////////////////////////////
// Main routine

if (document.getElementById)
window.onerror=new Function("return true")

var objActive;  // The object which event occured in
var act = 0;    // Flag during the action
var elmH = 0;   // Hue
var elmS = 128; // Saturation
var elmV = 255; // Value
var clrOrg;     // A color before the change
var TimerID;    // Timer ID

var IE = 0;
var Mozilla = 0;

// Browser check
var szUA = navigator.userAgent;
if (szUA.indexOf("MSIE 5.") >= 0) {
    IE = 5;
}
else if (szUA.indexOf("Mozilla/5.") >= 0) {
    Mozilla = 6;
}
else if(szUA.indexOf("MSIE 4.") >= 0) {
    IE = 4;
}
else if(szUA.indexOf("Mozilla/4.") >= 0) {
    Mozilla = 4;
}

if (IE >= 4) {
    document.onmouseover = doRainbowAnchor;
    document.onmouseout = stopRainbowAnchor;
}
else if (Mozilla >= 6) {
    document.captureEvents(Event.MOUSEOVER | Event.MOUSEOUT);
    document.onmouseover = Mozilla_doRainbowAnchor;
    document.onmouseout = Mozilla_stopRainbowAnchor;
}


//=============================================================================
// doRainbow
//  This function begins to change a color.
//=============================================================================
function doRainbow(obj)
{
    if (act == 0) {
        act = 1;
        if (obj)
            objActive = obj;
        else
            objActive = event.srcElement;
        clrOrg = objActive.style.color;
        TimerID = setInterval("ChangeColor()",100);
    }
}


//=============================================================================
// stopRainbow
//  This function stops to change a color.
//=============================================================================
function stopRainbow()
{
    if (act) {
        objActive.style.color = clrOrg;
        clearInterval(TimerID);
        act = 0;
    }
}


//=============================================================================
// doRainbowAnchor
//  This function begins to change a color. (of a anchor, automatically)
//=============================================================================
function doRainbowAnchor()
{
    if (act == 0) {
        var obj = event.srcElement;
        while (obj.tagName != 'A' && obj.tagName != 'BODY') {
            obj = obj.parentElement;
            if (obj.tagName == 'A' || obj.tagName == 'BODY')
                break;
        }

        if (obj.tagName == 'A' && obj.href != '') {
            objActive = obj;
            act = 1;
            clrOrg = objActive.style.color;
            TimerID = setInterval("ChangeColor()",100);
        }
    }
}


//=============================================================================
// stopRainbowAnchor
//  This function stops to change a color. (of a anchor, automatically)
//=============================================================================
function stopRainbowAnchor()
{
    if (act) {
        if (objActive.tagName == 'A') {
            objActive.style.color = clrOrg;
            clearInterval(TimerID);
            act = 0;
        }
    }
}


//=============================================================================
// Mozilla_doRainbowAnchor(for Netscape6 and Mozilla browser)
//  This function begins to change a color. (of a anchor, automatically)
//=============================================================================
function Mozilla_doRainbowAnchor(e)
{
    if (act == 0) {
        obj = e.target;
        while (obj.nodeName != 'A' && obj.nodeName != 'BODY') {
            obj = obj.parentNode;
            if (obj.nodeName == 'A' || obj.nodeName == 'BODY')
                break;
        }

        if (obj.nodeName == 'A' && obj.href != '') {
            objActive = obj;
            act = 1;
            clrOrg = obj.style.color;
            TimerID = setInterval("ChangeColor()",100);
        }
    }
}


//=============================================================================
// Mozilla_stopRainbowAnchor(for Netscape6 and Mozilla browser)
//  This function stops to change a color. (of a anchor, automatically)
//=============================================================================
function Mozilla_stopRainbowAnchor(e)
{
    if (act) {
        if (objActive.nodeName == 'A') {
            objActive.style.color = clrOrg;
            clearInterval(TimerID);
            act = 0;
        }
    }
}


//=============================================================================
// Change Color
//  This function changes a color actually.
//=============================================================================
function ChangeColor()
{
    objActive.style.color = makeColor();
}


//=============================================================================
// makeColor
//  This function makes rainbow colors.
//=============================================================================
function makeColor()
{
    // Don't you think Color Gamut to look like Rainbow?

    // HSVtoRGB
    if (elmS == 0) {
        elmR = elmV;    elmG = elmV;    elmB = elmV;
    }
    else {
        t1 = elmV;
        t2 = (255 - elmS) * elmV / 255;
        t3 = elmH % 60;
        t3 = (t1 - t2) * t3 / 60;

        if (elmH < 60) {
            elmR = t1;  elmB = t2;  elmG = t2 + t3;
        }
        else if (elmH < 120) {
            elmG = t1;  elmB = t2;  elmR = t1 - t3;
        }
        else if (elmH < 180) {
            elmG = t1;  elmR = t2;  elmB = t2 + t3;
        }
        else if (elmH < 240) {
            elmB = t1;  elmR = t2;  elmG = t1 - t3;
        }
        else if (elmH < 300) {
            elmB = t1;  elmG = t2;  elmR = t2 + t3;
        }
        else if (elmH < 360) {
            elmR = t1;  elmG = t2;  elmB = t1 - t3;
        }
        else {
            elmR = 0;   elmG = 0;   elmB = 0;
        }
    }

    elmR = Math.floor(elmR).toString(16);
    elmG = Math.floor(elmG).toString(16);
    elmB = Math.floor(elmB).toString(16);
    if (elmR.length == 1)    elmR = "0" + elmR;
    if (elmG.length == 1)    elmG = "0" + elmG;
    if (elmB.length == 1)    elmB = "0" + elmB;

    elmH = elmH + rate;
    if (elmH >= 360)
        elmH = 0;

    return '#' + elmR + elmG + elmB;
}
-->
</script>

The best thing to do here is to copy the script source above into a text or HTML editor. The click on FILE/SAVE AS to save it as a javascript file such as "rainbow.js". Then link to it on the pages you want it to have an effect on your links. Copy the source below to link to this file. Add the following to the <head>...</head> tag pair in your HTML source code.

TIP: If there are any links that you don't want to radiate these colors you can put the <font>...</font> tag pair inside the link. This turns the rainbow colors off. Below are 3 links. Pass your cursor over the links and you'll notice the last one "Fox News" doesn't have rainbow colors.

CNN | MSNBC | FoxNews

This will work wherever there is text. The source code below is for the links. Try passing your cursor over various parts of the form below to see what I did. Although I had to use onmoseover and onmouseout to make it happen.

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