VISUALIZZA L'ESEMPIO

Per inserire lo script, innanzitutto dobbiamo mettere questo codice all'interno del tag head:

<SCRIPT language="JavaScript"> <!-- // ------------- Browser Detector --------------- // Possible values for browser are: // "netscape" // "opera" <--(ewww) // "msie" <--(double ewww) // "robot" // "unknown" // Possible values for version are: // any numerical value (3, 2.02, 4.04, etc.) // 0 if unable to determine var browser = "unknown"; var version = 0; if (navigator.userAgent.indexOf("Opera") >= 0) browser = "opera"; else if (navigator.userAgent.indexOf("obot") >= 0) browser = "robot"; else if (navigator.appName.indexOf("etscape") >= 0) browser = "netscape"; else if (navigator.appName.indexOf("icrosoft") >= 0) browser = "msie"; version = parseFloat(navigator.appVersion); if (isNaN(version)) version = 0; if ((browser == "msie")&&(version == 2)) version = 3; // ------------------ Gradient Output -------------------- // Syntax for use: // gradient(TEXT_STRING_HERE,HEXCODES_STRING_HERE); // use in similar way you would use document.write(); // note, it cannot be used to return a string value. // gradient() takes two arguements. the first will // be the original pure text string. (no htmlcodes) // the second argument is a string of color hexcodes // seperated with spaces thru which the text should // progress. for example say you wanted to print out // the string "color gradient", and you wanted it to // progress from blue to red. a color code for blue // is 4444FF, and a color code for red is FF4444. // taking those two codes, and the original string, // somewhere in the body of the document you would // write within a tag the following: // gradient("color gradient","4444FF FF4444"); // if however, you wanted it to progress thru three // or more colors, its as simple as adding them to the // string of color codes. it is important to remember // however that the string must be color HEXCODES, and // not merely just color names, (e.x- "red", "yellow") // if this seems like too much trouble, then perhaps // you should try something simple like ripping off // some annoying status bar text scroller. =Þ // one last thing. if you overuse this script, i can // pretty much gaurantee people will hate your webpage. // the fact is, this javascript is memory intensive. if // you overdo it, you're crashing some visitors' browsers. // ------------------------------------------------------ // lookup table var tohex = new Array(256); var hex = "0123456789ABCDEF"; var count = 0; for (x=0; x<16; x++) { for (y=0; y<16; y++) { tohex[count] = hex.charAt(x) + hex.charAt(y); count++; } } //ColorCode constructor function ColorCode(hexcode) { if (hexcode.length == 7) { this.r = parseInt(hexcode.substring(1,3),16); this.g = parseInt(hexcode.substring(3,5),16); this.b = parseInt(hexcode.substring(5,7),16); } else if (hexcode.length == 6) { this.r = parseInt(hexcode.substring(0,2),16); this.g = parseInt(hexcode.substring(2,4),16); this.b = parseInt(hexcode.substring(4,6),16); } else { this.r = this.g = this.b = 0; alert("Error: ColorCode constructor failed"); } if (isNaN(this.r)||isNaN(this.g)||isNaN(this.b)) alert("Error: ColorCode constructor failed"); } // ColorList constructor function ColorList(hexcodes) { var i = 0; var c = 0; this.codes = new Array(Math.round(hexcodes.length/7)); while (i < hexcodes.length) { if (isNaN(parseInt(hexcodes.substring(i,i+6),16))) ++i; else { this.codes[c] = new ColorCode(hexcodes.substring(i,i+6)); i += 7; ++c; } } this.len = c; } function interpolate (x1, y1, x3, y3, x2) { if (x3 == x1) return y1 else return (x2-x1)*(y3-y1)/(x3-x1) + y1 } // x=index of letter, y=number of letters, z=number of colors function lowcolorindex (x, y, z) { if (y == 1) return 0 else return Math.floor( (x*(z-1))/(y-1) ) } function hicolorindex (x, y, z, low) { if ( low*(y-1) == x*(z-1) ) return low else if (y == 1) return 0 else return Math.floor( (x*(z-1))/(y-1) + 1 ) } function gradient (thetext,thecolors) { if (((browser == "netscape")||(browser == "msie")||(browser == "opera"))&&(version>=3.0)) { var colors = new ColorList(thecolors); var numcolors = colors.len; var numchars = thetext.length; var rr = 0; var gg = 0; var bb = 0; var lci = 0; //lower color index var hci = 0; //high color index for (i=0; i<numchars; ++i) { lci = lowcolorindex(i, numchars, numcolors); hci = hicolorindex(i, numchars, numcolors, lci); rr = Math.round(interpolate( lci/(numcolors-1), colors.codes[lci].r, hci/(numcolors-1), colors.codes[hci].r, i/(numchars-1))); gg = Math.round(interpolate( lci/(numcolors-1), colors.codes[lci].g, hci/(numcolors-1), colors.codes[hci].g, i/(numchars-1))); bb = Math.round(interpolate( lci/(numcolors-1), colors.codes[lci].b, hci/(numcolors-1), colors.codes[hci].b, i/(numchars-1))); if (browser == "opera") { rr = 255 - rr; gg = 255 - gg; bb = 255 - bb; } document.write(thetext.charAt(i).fontcolor(tohex[rr]+tohex[gg]+tohex[bb])); } } else document.write(thetext); // unrecognized browser, better not to attempt anything fancy } //--> </SCRIPT>

Adesso vediamo come si può inserire il testo sfumato, con questo esempio:

<SCRIPT language="JavaScript">
gradient("WebMasterPoint.org","FF0000 FFFFFF 0000FF");
document.write('<BR>');
gradient("Il punto di riferimento dei webmaster italiani","444444 DDDDDD 444444");
</SCRIPT>

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