APPLIQUER UN CHEMIN DE COULEUR SUR UN TEXTE ENTRÉ EN PARAMÈTRE...

     <script language="javascript" type="text/javascript">
     function Color(arg,ag,ab)
     {
    
     if((typeof(arg)=="number")&&(typeof(ag)=="number")&&(typeof(ab)=="number"))
     {
     this.red = arg;
     this.green = ag;
     this.blue = ab;
     }
     else
     {
     this.red = 0;
     this.green = 0;
     this.blue = 0;
     }
     }
     function d2h(d)
     {
     if ((d<16)&&(0<=d)) return "0" + d.toString(16);
     else return d.toString(16);
     }
    
     function h2d(h) {return parseInt(h,16);}
    
 function	ColorString(texte,tColors,style,fdebug) 
	{
		var  out = "";
		var sout="";
		debug = function  (idebug)
		{//alert("texte.length" + texte.length)
			switch(idebug)
			{
				case 0:sout="texte.length" + texte.length;break;
				case 1:sout+="\ndColor:" + dColor;break;
				case 2:sout+="<br>Nbre de lettre par partie : " +nbLettrepPartie;break;
				case 3:sout+="if(!(dColor * iColor < Lettre))<br>";break;
				case 4:sout="<br>vrai ou faux??";;break;
				case 5:sout+=dColor + "*" + iColor + "<=" + Lettre;break;
				case 6:sout+="\nicolor++\n";;break;
				case 7:sout+="iLettre:"+iLettre+"\tColor :"+TheColor+" \tLettre:'"+texte.charAt(Lettre)+"'\n";break;
				case 8:document.write(sout);
				case 9:sout+="\n" + dColor * iColor + "<" + Lettre
				default:sout+="null"; break;
			}
		}
		
		nbLettrepPartie = texte.length/(tColors.length-1);
		if(fdebug) debug(0);
		dColor = texte.length / (tColors.length-1); 
		if(fdebug)debug(1);
		if(fdebug)debug(2);
		if (dColor<1) dColor = 1;
		var iColor = 0;
		if(fdebug){debug(3);debug(8);}
		iLettre = 0;
		for(var Lettre = 0; Lettre<texte.length;Lettre++)// Parcours et écriture de toute les lettres
		{   if(fdebug){debug(4);debug(5);debug(9);}

			if(dColor * iColor <= Lettre)
			{	iLettre = 0;
				iColor++;
				if(fdebug)debug(6);
				dr = ( tColors[iColor].red   - tColors[iColor-1].red   ) / nbLettrepPartie;
				dg = ( tColors[iColor].green - tColors[iColor-1].green ) / nbLettrepPartie;
				db = ( tColors[iColor].blue  - tColors[iColor-1].blue  ) / nbLettrepPartie;
			}
			
			TheColor = "#" + d2h(Math.round(tColors[iColor-1].red + iLettre * dr)) +d2h(Math.round(tColors[iColor-1].green + iLettre * dg)) + d2h(Math.round(tColors[iColor-1].blue + iLettre * db))
			if(fdebug){debug(7);debug(8);}
			out+='<font '+style+' color="' + TheColor + '">' + texte.charAt(Lettre) + '</font>';
			
			iLettre++;
		}
		document.write(out);
	}
    
     var tColors = [new Color(00,00,255),new Color(255,255,255),new Color(255,0,0)]
     ColorString("0123456789abcdefghijklmnopqrstuvwxyz0123456789abcdefghijklmnopqrstuvwxyz",tColors,"",1);
     </script>