Today, let's talk about the regular:
Regular full-length regular expressions, also known as regular expressions. English: Regular expression, abbreviated as Reg.
and the regular expression is to deal with the string, set up a series of rules, which is his usage;
Features: Very high performance, convenient.
a regular notation:
1. Pass a parameter
var reg = new RegExp (' String to find () ');
Str.search (reg);
no Return-1 is found, one from left to right, and case-sensitive ;
2. Pass two parameters:
New RegExp (' String to find ', ' G ');
in this, G stands for: global: All;
shorthand for Regular:
var reg =//;
Some methods:
Str.search (reg); search location;
Str.match (reg); Match object;
str.replace (Reg, ' the character to be replaced by '), or: Str.replace (reg,function (s) {});
reg.test (otxt.value): Check if Otxt.value meet demand, return true if required, otherwise return false;
| |: OR;
|: Regular inside OR; (Regular is more lazy, more or less, as long as there is a satisfaction to play true;)
^: The beginning of the line; put in [] inside to represent the exclusion;
$: End of line;
some abbreviations:
I:ignore: Ignore
G:global: Global
M:multi-line: Multiple lines
about escape \:
\d:digital: Digital
\ n: line break;
\s:space: space;
\w:word: words;
\d: Non-digital;
\w: Non-word;
\s: Non-space;
.: any thing;
about []:
[abc]-->a|b|c;
[1-39]-->1 to 3, or 9
[A-z]--->a-z 26 lowercase letters;
[A-z]--->a-z 26 uppercase letters;
[0-9]--->0-9 digital--->\d;
[^0-9]---> Non-digital;--->\d
[^A-Z]---> Non-lowercase letters;
[^a-z]----> non-capital letters;
quantifier: {}
?--->{0,1}, there can be no, there is only one at most.
{n}: exactly n;/\d{3}/: exactly 3 digits;
{n,m} a minimum of n, up to M;
{1,} at least 1, no limit,---> +;
{0,} can be no, there is no limit to the number;----> *;
/ab+/--->abbbbbb;
/(AB) +/--->abababab;
+:n multiple;
Here are some examples of how to share a regular:
1. School check age. html
<script> window.onload=function () { var otxt=document.getelementbyid (' txt '); Otxt.oninput=function () { otxt.value=otxt.value.replace (/\d/, ') } } </script>2. Organize the format. html<script> window.onload=function () { var Otxt1=document.getelementbyid (' Txt1 '); var Otxt2=document.getelementbyid (' Txt2 '); var Obtn=document.getelementbyid (' btn '); Obtn.onclick=function () { //otxt2.value=otxt1.value.replace (/^/mg, ' ) otxt2.value= OTxt1.value.replace (/$/mg, ' Qwer ') } } </script>3. Check Chinese characters. html<script> window.onload=function () { var otxt=document.getelementbyid (' txt '); var Obtn=document.getelementbyid (' btn '); var reg=/^[\u4e00-\u9fa5]{2,6}$/; Obtn.onclick=function () { alert (reg.test (Otxt.value) }} //var reg=/[^\u4e00-\u9fa5]{2,6}$/*** the range of Chinese characters; } </script>4. Check the landline number. html<script> window.onload= function () { var otxt=document.getelementbyid (' txt '); var Obtn=document.getelementbyid (' btn '); var reg=/^ (0[1-9]\d{1,2}-)? [1-9]\d{6,7}$/; Obtn.onclick=function () { alert (reg.test (otxt.value) } }} </script>5. The input box can only enter numbers. html
<script> window.onload=function () { var otxt=document.getelementbyid (' txt '); Otxt.oninput=function () { otxt.value=otxt.value.replace (/\d/, ') } } </script></ Head><body><input type= "text" name= "" id= "TXT"/></body>6. Filter sensitive words 1.html
<script> var str= ' I'll be by your side you'll never look back, your every move like a heartbeat affects me all I'll be in your farinose you'll never let go no matter yesterday today and after the end of the day I must come back to do qingfengdian undisturbed once I'll take you to see the everlasting laughter in the sunny days I'm not going to go back to the day every day daily night waiting for the king called me to patrol the mountain King called me to patrol the mountain I put the car on the five rings Ah Five ring you die four ring more ring AH Five ring you are more than six ring one day you will fix to seven ring fix to seven ring What do you do more than the five rings two ring when I see you again see if I see you again some unspeakable weakness can only slowly grasp their own sometimes also secretly Tears sometimes also silently thought oneself also may have the possibility if the heaven arranges in the love and hate season to confuse suddenly too many words some unspeakable weak tenderness suddenly one day you are not in I hear I say ' var reg=/you | too much | one | daily every night | people/g ; document.write (Str.replace (reg,function (s) { var tmp= '; for (var i=0;i< s.length;i++) { tmp+= ' * '; } Return ' <span style= ' color:orangered; > ' +tmp+ ' </span> ' }) </script>7. Capitalize the first letter. html<script> window.onload=function () { var str= ' Come on baby '; document.write (Str.replace (/\w+/g,function (s) { return S.charat (0). toUpperCase () + s.substring (1); }) } </script>
The basic of regular expressions
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