Form validation and regular expression (2)

String Classes can support regular methods :

search=》 Returns the subscript of the matching string , Otherwise return to -1

match=》 If no matching text is found , return null. otherwise , It will return an array （ Depends on whether there is a global flag g）

replace=》 Returns a new string

split=》 Returns an array of strings

/*search() Method - Use regular expressions to retrieve abc*/

var str="helloabc";

console.log(str.search(/abc/));  //6

console.log(str.search(/ABC/));  //-1

 console.log(str.search(/ABC/i)); //6

/*match() Method - Use regular expressions to retrieve all numbers in a string */

var str="1 and 2 and 3";

console.log(str.match(/\d/)); //[1]

console.log(str.match(/efg/)); // null

console.log(str.match(/\d/g)); //[1,2,3]

/*replace() Method - Use "abc" Replace in string "yang"*/

var str="hello yang";

console.log(str.replace(/yang/,"abc")); //hello abc

var str="helloyang, How are you?yang";

console.log(str.replace(/yang/g,"abc")); //helloabc, How are you?abc

Replace... With a function

Second use replaceAll()

/*split() Method - Divide words into letters */

console.log("hello".split("")); //h e l l o

console.log("hello".split("",3)); //[h e l]

console.log("h1e2l3l4o".split(/\d/));  //hello

Regular verification

verification 26 A string of English letters

Validation consists of numbers and 26 A string of English letters

Verification by numbers 、 Letter 、 String of underscores

Verify Chinese characters

/* verification 26 A string of English letters */

var str="sgfhdfGIYYjhj";

var reg=/^[a-zA-Z]+$/;   // Once or more "+"

console.log(reg.test(str));

/* Validation consists of numbers and 26 A string of English letters */

var str="abc123DFjh";

var reg=/^[0-9a-zA-Z]+$/;

console.log(reg.test(str));

/* Verification by numbers 、 Letter 、 String of underscores */

var str="abc_123_DFjh";

var reg=/^\w+$/;

console.log(reg.test(str));

/* Verify Chinese characters */

var str=" My motherland ";

var reg=/^[\u4e00-\u9fa5]+$/

console.log(reg.test(str));

practice 1：

Use regular validation to verify the following requirements

A string with spaces at the beginning and end （ Verify and clear the front 、 Back 、 Before and after and all the spaces ）

Verify phone number

Verify email

/* Verify the string with spaces at the beginning and end */

        varstr= "    abc   "

        varreg= /^\s+ /   // Go to the front space

        console. log( str. replace( reg, ''));

        // Go to the space behind

        varstr= ' abc  '

        varreg= /\s+ $/

        console. log( str. replace( reg, ''));

        // Go to the space before and after

        varstr= ' abc  '

        varreg= /^\s+ |\s+ $/g

        console. log( str. replace( reg, ''));

        // Clear all spaces

        varstr= ' abc hy  '

        varreg= /\s+ /g

        console. log( str. replace( reg, ''));

        /* Verify phone number */

        varstr= "13502023437";

        varreg= /^1[34578][0-9]{9} $/

       varreg= /^1[34578]\d{9} $/

        console. log( reg. test( str));

        /* Verify email */

        varstr= "[email protected]";

       /*  \ Represents an escape character , hold . Convert to string , And use () grouping , Namely .com perhaps .cn As a group

        varreg= /^[a-zA-Z0-9_-]+ @[a-zA-Z0-9_-]+ (\.[a-zA-Z0-9_-]+ )+ $/

            /*  It can be abbreviated as follows

         var reg =/^[\w-][email protected][\w-]+(\.[\w-]+)+$/

        console. log( reg. test( str));

practice 2：

Use regular to add brackets to the numbers in the following string

var str='abc123efg';  become 'abc[1][2][3]efg'

varstr= 'abc345efg';

        varreg1 = /\d/g;

        vararr = str. split( '');

        for( vari= 0; i< arr. length; i++)

        {

            if( isNaN( arr[ i])== false)

            {

                arr[ i] = '['+ arr[ i]+ ']';

            }

        }

        str2 = arr. join( '');

        alert( str2);

Use isNaN There is one   defects , If there is a space, he will also return fales, So we use regular better , Pictured :

Comprehensive case - Form validation

user.οnblur=function(){

           reg=/^[\w\u4e00-\u9fa5]{6,12}$/;

           if(user.value==''){

            user_p.innerHTML='<i class="err"></i> Can't be empty ';

            return false;

        }

        else if(!reg.test(user.value)){

            user_p.innerHTML='<i class="err"></i> The length is not in the range or there are illegal characters '

            return false;

        }

        // The user name input is consistent with the requirements

        else{

            user_p.innerHTML='<i class="ok"></i> correct '

            return true

        }

}

Form validation — Login password requirements

psd.οnblur=function(){

        var reg=/^\w{6,12}$/;

        var reg1=/[^0-9]/;

        var reg2=/[^a-zA-Z]/;

        if(psd.value==''){

            psd_p.innerHTML='<i class="err"></i> Can't be empty ';

            return false;

        }

        // The length is in 6-12 Between Alphanumeric underline

        else if(!reg.test(psd.value)){

            psd_p.innerHTML='<i class="err"></i> The length is not in the range or there are illegal characters '

            return false;

        }

  else if(!reg1.test(psd.value))

        {

            psd_p.innerHTML='<i class="err"></i> It can't be all Numbers '

            return false;

        }

        else if(!reg2.test(psd.value)){

            psd_p.innerHTML='<i class="err"></i> Not all letters '

            return false;

        }

        // The password input is consistent with the requirements

        else{

            psd_p.innerHTML='<i class="ok"></i> correct '

            return true;

        }

Form validation — Confirm password requirements

psd2.οnblur=function(){

        if(psd2.value==""){

            psd2_p.innerHTML='<i class="err"></i> Can't be empty ';

            return false;

        }

        // The two passwords are inconsistent

        else if(psd.value!=psd2.value){

            psd2_p.innerHTML='<i class="err"></i> The two passwords don't match ';

            return false;

        }

        // The password input is consistent with the requirements

        else{

            psd2_p.innerHTML='<i class="ok"></i> correct '

            return true;

        }

}