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Give it a with the link below. If you enter a name longer than 10 ? acte? ou get a? ror ? t. O? wise, you get a greeting alert!
? align="? "> ? ? t language="JavaScript" type="text/JavaS? t"> ? align="? "> Example:? e me? r name! ? align="? "> ch? ? an> Using the ch? ? hod,? can fin? t what chara? is filling a designated? ition within? tring. Basic? ? allows you to find out ? cha? er is first, second, third, and so on. The i? ? thi? o remember is th? hen dealing with the? ition of a chara? , the count ? ts at zero, not one. So the ? t character is actually ? ? ion zero.
t color="#FFFFFF"> As wi? he l? h method, we? ign the stri? o a variable, and th? ? he dot operator to call the ? At method. The charAt method takes a? gument, whic? the? itio? ? ? the cha? er it should? urn. So, if ? ant to find the ? t character in our "? ari"? ing, we would do it ? ? ? ? >
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? tim? ? ill get an a? telling? that "The last ? acte? i." Thi? fun? n't it?
? align="? "> indexO? pan> ? align="? ">? we get ? ? eall? n method of indexOf. This method? s you check for aracter or even a small stri? ithin th? rren? ring, and returns the position at which ? cha? er o? ring begins. Again, reme? that the positi? ? s counting at 0, so if i? ? ? ? ero, it means your chara? or string begin? the? cha? er. Also, indexOf has a usef? ? n value of -1 if the cha? er o? ring? searched fo? ? contain? ithin th? ring. And finally, if the character ? tring you search? occurs more than once, indexOf ? rns ? the? st appearance of? r character ? tring.? t, l? find the 'a'. N? oblem, a we use the dot ? ? . IndexOf al? ? an ? ? like ch? does, b? his time the argumen? the cha? er o? ring we are looking for:
Notice th? ote mark? ound the argument of a. ? tel? he b? ? o look f? hat string, whic? the? e of argument yo? ? end for indexOf to f? ion ? ? . This code will send ba? ? ? ion ? he letter a. The ale? ill say "The a i? ? ition 4." Look out letter a,? ? e been found!
L? ? look for the le? 'r' in ? rari". As you can see, 'r' is in the? ing three times.? ? , on? he f? ? earance will be ? rned? ? ition 2. N? he a? ? s "T? is ? ? ion 2." The other r'? ? itions 3 and 5 are n? he f? , so the? e not returned. This one chec? o be? e the vi? ? ered the? p://? t of the add? . If? ? sho? he e? alert and g? the viewer a chance to enter th? l again. Of ? se, you can cut down on the number of fo? ten ? :// beginnings b? ing ? :// ? he d? ? alue? the prompt ? ead of nothing: Of c? ? ? iewer could delete i? accident (o? en o? ? e), ? he check? ? till be ? hwhile. You coul? en go a ? ? ? and be sure that there is at least one dot (.) ? he address as well. ? ? , the vi? ? ld need ave ? ring? s a dot and hopefully a com or net a? ward ( like ? ? ww.f? ebknowledge.com). We can? o check for the ? :// ? ell,? ? ? ample: You c? ry o? ? ? t below,? e so? rl a? ? hat it does!
Of? rse, it ? till? goi? o totally eliminate ? ? or bad ? ? omeone could? t enter ? ://.? ? helps a? tle bit.
Well, that does it for now, l? ? e on to .
function? _url? ? ? ? ? ? ('Enter ? web page URL!',? p://');
var ? rotocol_? our_url.indexOf(? p://');
var is_dot_ok=yo? rl.i? Of('.');
if ? _protocol_ok==-1? ? ? _ok==-1)?
? t('E? : Yo? ? hould begin with? p:// and? ? least one dot (.)!');
? _url();
}
else
alert('Thanks!'?
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