<\/span><\/h2>\n\n\n\n\u0110o\u1ea1n code m\u1eabu \u0111\u1ec3 l\u1ea5y d\u1eef li\u1ec7u t\u1eeb th\u1ebb input: <\/p>\n\n\n\n
var ten = document.forms[\"myForm\"][\"ten\"].value;<\/code><\/pre>\n\n\n\nNh\u01b0 \u0111o\u1ea1n code tr\u00ean c\u00f3 ngh\u0129a l\u00e0 b\u1ea1n l\u1ea5y gi\u00e1 tr\u1ecb c\u1ee7a th\u1ebb input c\u00f3 t\u00ean l\u00e0 \u201cten\u201d<\/em> trong Form c\u00f3 t\u00ean l\u00e0 \u201cmyForm\u201d<\/em> v\u00e0 g\u00e1n gi\u00e1 tr\u1ecb l\u1ea5y \u0111\u01b0\u1ee3c n\u00e0y v\u00e0o bi\u1ebfn var ten<\/em><\/p>\n\n\n\nT\u01b0\u01a1ng t\u1ef1 cho email: <\/p>\n\n\n\n
var email=document.forms[\"myForm\"][\"email\"].value;<\/code><\/pre>\n\n\n\n
\n\n\n\n<\/span>Kh\u00f4ng \u0111\u01b0\u1ee3c b\u1ecf tr\u1ed1ng d\u1eef li\u1ec7u:<\/span><\/h2>\n\n\n\nvar ten = document.forms[\"myForm\"][\"ten\"].value;\nif (ten == \"\") {\nalert(\"T\u00ean kh\u00f4ng \u0111\u01b0\u1ee3c \u0111\u1ec3 tr\u1ed1ng\");\nreturn false;\n}<\/code><\/pre>\n\n\n\nTheo \u0111\u00f3, sau khi l\u1ea5y \u0111\u01b0\u1ee3c d\u1eef li\u1ec7u t\u1eeb th\u1ebb input v\u00e0 g\u00e1n v\u00e0o bi\u00ean ten<\/em>, ch\u01b0\u01a1ng tr\u00ecnh d\u00f9ng h\u00e0m if \u0111\u1ec3 ki\u1ec3m tra ten<\/em> c\u00f3 r\u1ed7ng hay kh\u00f4ng \u2013 if(ten==\"\")<\/code>. N\u1ebfu th\u1ecfa m\u00e3n \u0111i\u1ec1u ki\u1ec7n r\u1ed7ng s\u1ebd c\u00f3 h\u1ed9p th\u00f4ng b\u00e1o \u201cT\u00ean kh\u00f4ng \u0111\u01b0\u1ee3c \u0111\u1ec3 tr\u1ed1ng\u201d v\u00e0 ta d\u00f9ng h\u00e0m alert \u0111\u1ec3 \u0111i\u1ec1u khi\u1ec3n t\u00e1c v\u1ee5 n\u00e0y, cu\u1ed1i c\u00f9ng return false.<\/p>\n\n\n\nKi\u1ec3m tra d\u1eef li\u1ec7u nh\u1eadp v\u00e0o c\u00f3 ph\u1ea3i l\u00e0 s\u1ed1 kh\u00f4ng<\/h3>\n\n\n\nvar dienThoai = document.forms[\"myForm\"][\"dienThoai\"].value;\nvar kiemTraDT = isNaN(dienThoai);\nif (kiemTraDT == true) {\nalert(\"\u0110i\u1ec7n tho\u1ea1i ph\u1ea3i \u0111\u1ec3 \u1edf \u0111\u1ecbnh d\u1ea1ng s\u1ed1\");\nreturn false;\n}<\/code><\/pre>\n\n\n\nH\u00e0m d\u00f9ng \u0111\u1ec3 ki\u1ec3m tra s\u1ed1 \u0111\u00f3 l\u00e0 isNaN<\/code> \u2013 vi\u1ebft t\u1eaft c\u1ee7a is Not a Number. N\u1ebfu isNaN tr\u1ea3 v\u1ec1 gi\u00e1 tr\u1ecb TRUE<\/code> ngh\u0129a l\u00e0 \u0111\u00f3 kh\u00f4ng ph\u1ea3i l\u00e0 m\u1ed9t s\u1ed1.<\/p>\n\n\n\n
\n\n\n\n<\/span>Ki\u1ec3m tra Email h\u1ee3p chu\u1ea9n<\/span><\/h2>\n\n\n\nC\u00f3 l\u1ebd v\u1edbi \u0111a s\u1ed1 m\u1ecdi ng\u01b0\u1eddi th\u00ec \u0111\u00e2y l\u00e0 code ph\u1ee9c t\u1ea1p nh\u1ea5t (v\u1edbi t\u00f4i c\u0169ng th\u1ebf). \u0110\u1ecba ch\u1ec9 email ch\u00ednh x\u00e1c ph\u1ea3i th\u1ecfa m\u00e3n \u0111i\u1ec1u ki\u1ec7n sau:<\/p>\n\n\n\n
- Ph\u1ea3i c\u00f3 k\u00fd t\u1ef1 @;<\/li>
- Tr\u01b0\u1edbc @ ph\u1ea3i c\u00f3 \u00edt nh\u1ea5t 1 k\u00fd t\u1ef1;<\/li>
- Ph\u1ea3i c\u00f3 \u00edt nh\u1ea5t 1 d\u1ea5u ch\u1ea5m trong email;<\/li>
- Ph\u1ea3i c\u00f3 \u00edt nh\u1ea5t 1 k\u00fd t\u1ef1 \u0111\u1ee9ng gi\u1eefa @ v\u00e0 d\u1ea5u ch\u1ea5m;<\/li>
- D\u1ea5u ch\u1ea5m kh\u00f4ng \u0111\u01b0\u1ee3c \u0111\u1ee9ng \u1edf v\u1ecb tr\u00ed cu\u1ed1i c\u00f9ng;<\/li><\/ul>\n\n\n\n
Code m\u1eabu:<\/p>\n\n\n\n
var email=document.forms[\"myForm\"][\"email\"].value;\nvar aCong=email.indexOf(\"@\");\nvar dauCham = email.lastIndexOf(\".\");if (email == \"\") {\nalert(\"Email kh\u00f4ng \u0111\u01b0\u1ee3c \u0111\u1ec3 tr\u1ed1ng\");\nreturn false;\n}else if ((aCong<1) || (dauCham<aCong+2) || (dauCham+2>email.length)) {\nalert(\"Email b\u1ea1n \u0111i\u1ec1n kh\u00f4ng ch\u00ednh x\u00e1c\");\nreturn false;\n}<\/code><\/pre>\n\n\n\nCh\u00fang ta c\u1ea7n ch\u00fa \u00fd \u0111\u1ebfn l\u1ec7nh indexOf<\/code>, n\u00f3 s\u1ebd x\u00e1c \u0111\u1ecbnh s\u1ed1 k\u00fd t\u1ef1 \u0111\u1ee9ng tr\u01b0\u1edbc n\u00f3 t\u00ednh t\u1eeb tr\u00e1i sang. V\u00ed d\u1ee5, email ab@xy.com c\u00f3 gi\u00e1 tr\u1ecb email.indexOf(\"@\")<\/code> l\u00e0 2 v\u00ec c\u00f3 2 k\u00fd t\u1ef1 l\u00e0 a v\u00e0 b \u0111\u1ee9ng tr\u01b0\u1edbc @email.indexOf(\".\")<\/code> c\u00f3 gi\u00e1 tr\u1ecb l\u00e0 5 v\u00ec c\u00f3 5 k\u00fd t\u1ef1 \u0111\u1ee9ng tr\u01b0\u1edbc d\u1ea5u . l\u00e0 a, b, @, x, y;<\/p>\n\n\n\nN\u1ebfu kh\u00f4ng c\u00f3 k\u00fd t\u1ef1 c\u1ea7n t\u00ecm trong chu\u1ed7i, h\u00e0m indexOf<\/code> s\u1ebd tr\u1ea3 v\u1ec1 -1.<\/p>\n\n\n\n\u0110\u1ebfn \u0111\u00e2y b\u1ea1n t\u1ef1 h\u1ecfi email.lastIndexOf(\".\")<\/code> c\u00f3 \u00fd ngh\u0129a g\u00ec. H\u1ebft s\u1ee9c ch\u00fa \u00fd ch\u1eef last. L\u1ec7nh n\u00e0y c\u0169ng l\u00e0 x\u00e1c \u0111\u1ecbnh s\u1ed1 k\u00fd t\u1ef1 \u0111\u1ee9ng tr\u01b0\u1edbc d\u1ea5u ch\u1ea5m nh\u01b0ng l\u00e0 d\u1ea5u ch\u1ea5m cu\u1ed1i c\u00f9ng. <\/p>\n\n\n\nCh\u1eb3ng h\u1ea1n email xyz.com@gmail.com, th\u1ebf th\u00ec d\u1ea5u ch\u1ea5m cu\u1ed1i c\u00f9ng l\u00e0 d\u1ea5u ch\u1ea5m sau ch\u1eef gmail ch\u1ee9 kh\u00f4ng ph\u1ea3i sau ch\u1eef xyz. <\/p>\n\n\n\n
Gi\u1edd ch\u00fang ta c\u00f9ng t\u00ecm hi\u1ec3u \u00fd ngh\u0129a code:<\/p>\n\n\n\n
var aCong=email.indexOf(\"@\");if (aCong<1)<\/code><\/pre>\n\n\n\nCh\u1ec9 c\u00f3 2 tr\u01b0\u1eddng h\u1ee3p x\u1ea3y ra khi aCong<1:<\/p>\n\n\n\n
- Kh\u00f4ng c\u00f3 @ trong \u0111\u1ecba ch\u1ec9 email, l\u00fac n\u00e0y
email.indexOf(\"@\") = -1<\/code><\/li>- aCong = 0, ngh\u0129a l\u00e0 kh\u00f4ng c\u00f3 k\u00fd t\u1ef1 n\u00e0o \u0111\u1ee9ng tr\u01b0\u1edbc @, hay email nh\u1eadp v\u00e0o c\u00f3 d\u1ea1ng @klm.com \u2013 t\u1ee9c l\u00e0 kh\u00f4ng h\u1ee3p chu\u1ea9n<\/li>
- V\u1eady l\u00e0 v\u1edbi c\u00e2u l\u1ec7nh tr\u00ean ta \u0111\u00e3 \u00e9p d\u1eef li\u1ec7u ph\u1ea3i c\u00f3 @, v\u00e0 tr\u01b0\u1edbc @ ph\u1ea3i c\u00f3 k\u00fd t\u1ef1<\/li><\/ul>\n\n\n\n
Sau @ ph\u1ea3i c\u00f3 \u00edt nh\u1ea5t 1 k\u00fd t\u1ef1 sau \u0111\u00f3 m\u1edbi \u0111\u1ebfn d\u1ea5u ch\u1ea5m do \u0111\u00f3, email h\u1ee3p chu\u1ea9n th\u00ec s\u1ed1 k\u00fd t\u1ef1 \u0111\u1ee9ng tr\u01b0\u1edbc d\u1ea5u ch\u1ea5m lu\u00f4n l\u1edbn h\u01a1n s\u1ed1 k\u00fd t\u1ef1 \u0111\u1ee9ng tr\u01b0\u1edbc @ \u00edt nh\u1ea5t 2 \u0111\u01a1n v\u1ecb \u2013 t\u1ee9c l\u00e0 dauCham >= aCong + 2<\/code>, ng\u01b0\u1ee3c l\u1ea1i \u0111i\u1ec1u n\u00e0y th\u00ec email \u0111\u00f3 kh\u00f4ng h\u1ee3p l\u1ec7, n\u00f3i c\u00e1ch kh\u00e1c l\u00e0: dauCham < aCong + 2<\/code><\/p>\n\n\n\nL\u1ec7nh tr\u00ean ch\u00fang ta \u0111\u00e3 \u00e9p ph\u1ea3i t\u1ed3n t\u1ea1i d\u1ea5u ch\u1ea5m trong email, ngo\u00e0i ra n\u00f3 c\u0169ng bu\u1ed9c gi\u1eefa d\u1ea5u ch\u1ea5m cu\u1ed1i c\u00f9ng v\u00e0 email ph\u1ea3i c\u00f3 \u00edt nh\u1ea5t 1 k\u00fd t\u1ef1.<\/p>\n\n\n\n
Ti\u1ebfp \u0111\u1ebfn ta xem x\u00e9t c\u00e2u l\u1ec7nh ng\u0103n kh\u00f4ng cho d\u1ea5u ch\u1ea5m l\u00e0 k\u00fd t\u1ef1 cu\u1ed1i c\u00f9ng trong email.<\/p>\n\n\n\n
var dauCham = email.lastIndexOf(\".\");dauCham+2>email.length<\/code><\/pre>\n\n\n\nemail.length<\/code> x\u00e1c \u0111\u1ecbnh s\u1ed1 k\u00fd t\u1ef1 c\u1ee7a chu\u1ed7i email<\/li>- Sau d\u1ea5u ch\u1ea5m cu\u1ed1i c\u00f9ng ph\u1ea3i c\u00f3 \u00edt nh\u1ea5t 1 k\u00fd t\u1ef1 do v\u1eady n\u1ebfu
dauCham + 2 > email.length<\/code> ngh\u0129a l\u00e0 email \u0111\u00f3 kh\u00f4ng h\u1ee3p chu\u1ea9n.<\/li><\/ul>\n","protected":false},"excerpt":{"rendered":"L\u00e0m form b\u1eb1ng HTML v\u00e0 ch\u1ec9nh s\u1eeda l\u1ea1i giao di\u1ec7n cho \u0111\u1eb9p v\u1edbi CSS kh\u00f4ng kh\u00f3, b\u1ea1n ch\u1ec9 c\u1ea7n nh\u1edb m\u1ea5y c\u00e1i input type l\u00e0 OK. V\u1ea5n \u0111\u1ec1 n\u1eb1m \u1edf Validate, t\u1ee9c l\u00e0 chu\u1ea9n h\u00f3a d\u1eef li\u1ec7u nh\u1eadp v\u00e0o v\u00e0 m\u1ed9t s\u1ed1 y\u00eau c\u1ea7u kh\u00e1c n\u1eefa. HTML5 l\u00e0m form c\u0169ng r\u1ea5t t\u1ed1t, nh\u01b0ng c\u00f3 h\u1ea1n …<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[236],"tags":[],"yoast_head":"\n
T\u1ea1o Form \u0111\u0103ng k\u00fd b\u1eb1ng JavaScript v\u00e0 th\u1ebb input • Ki\u1ebfn c\u00e0ng<\/title>\n\n\n\n\n\n\n\n\n\n\n\n\n\n\t\n\t\n\t\n","yoast_head_json":{"title":"T\u1ea1o Form \u0111\u0103ng k\u00fd b\u1eb1ng JavaScript v\u00e0 th\u1ebb input • Ki\u1ebfn c\u00e0ng","robots":{"index":"index","follow":"follow","max-snippet":"max-snippet:-1","max-image-preview":"max-image-preview:large","max-video-preview":"max-video-preview:-1"},"canonical":"https:\/\/kiencang.net\/tao-form-dang-ky-bang-javascript-va-the-input\/","og_locale":"vi_VN","og_type":"article","og_title":"T\u1ea1o Form \u0111\u0103ng k\u00fd b\u1eb1ng JavaScript v\u00e0 th\u1ebb input • Ki\u1ebfn c\u00e0ng","og_description":"L\u00e0m form b\u1eb1ng HTML v\u00e0 ch\u1ec9nh s\u1eeda l\u1ea1i giao di\u1ec7n cho \u0111\u1eb9p v\u1edbi CSS kh\u00f4ng kh\u00f3, b\u1ea1n ch\u1ec9 c\u1ea7n nh\u1edb m\u1ea5y c\u00e1i input type l\u00e0 OK. V\u1ea5n \u0111\u1ec1 n\u1eb1m \u1edf Validate, t\u1ee9c l\u00e0 chu\u1ea9n h\u00f3a d\u1eef li\u1ec7u nh\u1eadp v\u00e0o v\u00e0 m\u1ed9t s\u1ed1 y\u00eau c\u1ea7u kh\u00e1c n\u1eefa. 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