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It was once rumored that Pokerstars were going to be setting up a vBulletin forum where they would allow different players from around the world to discuss strategies with team Pokerstars.
Miscellaneous FAQ
| Use multiple functions in event handlers |
There are two ways of accomplishing this. You can place all the functions inside the command like this (using onmouseover attribute and the body tags as a examples):
<a href="#" onmouseover="func1();func2();">link text</a>" <body onload="func1();func2();"> You can also use a single function to call two other functions:
<script type="text/javascript">
//<![CDATA[
function doBoth()
{
func1();
func2();
}
function func1(){alert("Function 1");}
function func2(){alert("Function 2");}
//]]>
</script>
Then call the doBoth() function in your event handler:
<a href="#" onmouseover="doBoth();">Try it here</a> <body onload="doBoth();"> |
| Stack overflow error message |
You have a loop in your script and are running out of memory when running it. Be very careful when debugging - if you insert an alert(); in the wrong place you'll end up rebooting your machine! |
| Null or not an object error message |
The four common reasons for a 'null or not an object' error message are:
Remember, javascript is case-sensitive, so myForm and MyForm are not the same thing. 2) accessing an object before it is declared: All objects must be declared (and usually defined with a value) before they can be accessed. So if you must say something like:
<script type="text/javascript">
//<![CDATA[
document.myForm.myText.value = 'hello';
//]]>
</script>
<body>
<form name="myForm">
<input type="text" name="myText">
</form>
</body>it will throw an error. To fix it, make sure it is either inside a function or executed after the HTML is loaded.
For example: <script language="javascript">
function doit() {
document.myForm.myText.value = 'hello';
}
//]]>
</script>
<body onLoad='doit()'>
<form name="myForm">
<input type="text" name="myText">
</form>
Or,
<body>
<form name="myForm">
<input type="text" name="myText">
</form>
<script type="text/javascript">
//<![CDATA[
document.myForm.myText.value = 'hello';
//]]>
</script>
3) accessing an object that is never declared/defined:
If you are accessing an object through a loop, remember that html and javascript begin counting with zero (0). So, the following array and loop: var myArray = new Array(1,2,3);
for (i = 0; i <= myArray.length; i++)
alert(myArray[i]);will cause an error because there is no 'myArray[3]'. To fix it, the loop should look something like this:
for (i = 0; i < myArray.length; i++) alert(myArray[i]); 4) accessing the wrong object:
Although the following is not an error, it will cause loss of hair and time. Remember, computers are easily confused, so do not use keywords/reserved words (name, form, select, etc) as variable names. The following will perform as expected -- by the computer, but unfortunately not by you: <script type="text/javascript">
//<![CDATA[
var window.name = 'winName';
function doit(name)
{
alert(name)
}
//]]>
</script>
<form>
<input type="text" name="name" onBlur="doit(this.name)">
</form>You might also want to check out this thread. |
| Password protect a page with JavaScript |
JavaScript password protection is commonly insecure and therefore often ineffective. If you are protecting anything important, you should pursue another option such as a server-side language or the use of an .htaccess file. If you want to look for some JavaScripts for password protection, try this link: http://javascript.internet.com/passwords/ |
| Make a Print This Page button |
Place this function in your page:
<script type="text/javascript">
//<![CDATA[
function printit(){
if (window.print)
window.print() ;
else if (document.all) {
var WebBrowser = 'CLASSID="CLSID:8856F961-340A-11D0-A96B-00C04FD705A2">';
document.body.insertAdjacentHTML('beforeEnd', WebBrowser);
WebBrowser1.ExecWB(6, 6); //Use a 1 vs. a 6 for a prompting dialog box
WebBrowser1.outerHTML = "";
}
}
//]]>
</script>
Be sure the var WebBrowser ... all goes on a single line. Then call it with a button or link:
<a href="#" onclick="printit();return false">Print this page</a> |
| Read or write CSS values with JavaScript |
You can access css style properties via an object's style attribute:
object.style.styleattribute = value;The object would be an HTML element such as "<div>". The style attribute would be the script version of the attribute name, e.g., backgroundImage or borderTopColor. This part is actually easier than it looks if you remember a general rule: the attribute name must have any hyphens removed and the letter following the hyphen must be in upper case; so line-height becomes lineHeight,
scrollbar-3dlight-color becomes scrollbar3dLightColor, etc
So now we get: document.getElementById("thistag").style.backgroundImage = value;The value for a background image is url(imageaddress), so this must be passed as a string:
document.getElementById("thistag").style.backgroundImage = "url(http://www.webxpertz.net/faqs/jsfaq/misc/images/mybackground.gif)";Try it by putting your mouse here |
| Hexadecimal to Decimal and Decimal to Hexadecimal conversion |
How do I convert from Decimal to Hexidecimal?
How do I convert from Hexidecimal to Decimal? Like this: function hex(n) {var h=parseInt(n).toString(16); return (h.length%2)?"0"+h:h}
function dec(n) {return parseInt(n,16);} |
| Detect the mouse position |
This is cross-browser compatible from NS4 and IE4 upwards.
<html>
<head>
<title> Position </title>
</head>
<body>
<script type="text/javascript">
//<![CDATA[
//tell Netscape to catch mouse movements
if (document.layers) document.captureEvents(Event.MOUSEMOVE)
//when you detect a mouse movement, do this function
document.onmousemove = chasecur;
//id of the div to play with
var chasediv="myarea";
function chasecur(ns) {
var X = 0;
var Y = 0;
//grab the coordinates
if (document.all) {
X = event.clientX + document.body.scrollLeft;
Y = event.clientY + document.body.scrollTop;
}
else{
X = ns.pageX;
Y = ns.pageY;
}
//grab the div and move it where you want it
thisthing=getthing(chasediv);
thisthing.left = X+10;
thisthing.top = Y;
//put the coordinates into the div
content(chasediv,"Pos: x="+X+", y="+Y);
return true;
}
function getthing(which){
//if it's Internet Explorer, grab it using the "all" collection
if (document.all)
return document.all(which).style;
else if (document.getElementById)
//if it's Netscape 6+, grab it using the DOM function
return document.getElementById(which).style;
//if it's Netscape 4, grab it from the Layers
else if (document.layers)
return document.layers[which];
}
function content(which,what){
var x;
//if it's Netscape 4, write the value into the Layer's document
if (document.layers){
x = document.layers[which].document;
x.open();
x.write(what);
x.close();
}
else {
//if it's Netscape or IE 6+, change the content of the DIV
if (document.all)
x = document.all(which);
else
x= document.getElementById(which);
x.innerHTML = what;
}
}
//]]>
</script>
<div id="myarea" style='position:absolute;top:0px;left:0px'> </div>
</body>
</html> |
| Prevent left-clicking of a download link |
This will block a download link from being opened with a left-click, forcing viewers to right-click
and save the target file to disk or open in another window:
<a href="something.zyx" onclick="alert('Message of your choice');return false">Get something Here</a> |
| Remove the dotted line around a link |
Remove the focus from the link as soon as it receives it:
<a href="url" onfocus="this.blur()" ">Text</a> Tab to this link:
|
| Make a link that will act like the browser back button |
This can be accomplished with:
<a href="javascript:history.go(-1)">Go Back</a> |
| Make a page that can only be accessed from one of my links |
All you need to do is check the document.referrer - the easiest way to do this is with a reqular expression. The following example will only allow you to see the page from a link from a webxpertz.net site: |
| Set the target attribute for a link in XHTML |
Under XHTML strict, the target attribute for a link (or anchor) element is not recognised and thus will not validate. It is, however, still a part of the XHTML DOM and can be set via script, either singly or en masse:
<a href="http://google.com" onclick="this.target='_blank'">Go to Google</a> or:
<script type="text/javascript">
//<![CDATA[
function setTarget(){
var a = document.getElementsByTagName("a");
for(var i = 0;i < a.length;i++){
a[i].target = "_blank";
}
}
//]]>
onload=setTarget;
</script> |
| How to dynamically create web-safe hex-codes |
This script is courtesy of Roland Alfonso
<script type="text/javascript">
//<![CDATA[
/* 'rgb'(default)|'hex' */
function getWebsafe(form) {
var colours = [];
var toHex = form=='#';
var C = toHex
? ['00','33','66','99','cc','ff']
: ['00','51','102','153','204','255'];
var k = 216, f = Math.floor;
if(toHex) while(k--) colours[k]='#'+C[f(k/36)%6]+C[f(k/6)%6]+C[k%6];
else while(k--) colours[k]='rgb('+C[f(k/36)%6]+','+C[f(k/6)%6]+','+C[k%6]+')';
return colours;
}
// Just does #hex
function getHex216(){
var colours = [];
var hex = ['00','33','66','99','cc','ff'];
var k = 216, f = Math.floor;
while(k--) colours[k] = '#'+hex[f(k/36)%6]+hex[f(k/6)%6]+hex[k%6];
return colours;
}
String.prototype.toCSSColor = function(form){
var S,I = parseInt,hex,isHexForm=this.length<8;
// to rgb(,,) form //
if(form!='#'){
if(!isHexForm) return this+'';
// conv. #abc to #aabbcc
var S = ( this.length>4 ? this:this.replace(/\w/g,'$&$&') ).match(/\w{2}/g);
return 'rgb('+I(S[0],16)+','+I(S[1],16)+','+I(S[2],16)+')';
} else { // to #hex form //
if(isHexForm) return this+'';
var S = this.match(/\d+/g);
return ('#'+hx(S[0])+hx(S[1])+hx(S[2])).toUpperCase();
}
function hx(sDec){ // conv. decStr to hexStr; (?) add leading 0 ;
return(hex=I(sDec).toString(16)).length==1? 0+hex:hex;
}
}
/*-----------------------------------------------------------------------
NOTES: String.prototype.toCSSColor
- Not case-sensitive
- #abc form accepted
- ! '#abc'.toCSSColor('#') --> '#abc' (no conversion to #aabbcc)
- ! No error checking
- ! Doesn't accept colorNames (yet)
hex = '#0033FF'
sHex = '#03F'
dec = 'rgb(0,51,255)'
hex.toCSSColor() -->
sHex.toCSSColor() -->
dec.toCSSColor() --> 'rgb(0,51,255)'
dec.toCSSColor('#') -->
sHex.toCSSColor('#') -->
hex.toCSSColor('#') --> '#0033FF'
-----------------------------------------------------------------------
*/
//]]>
</script> |
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