{"id":20220,"date":"2013-08-23T07:27:00","date_gmt":"2013-08-23T07:27:00","guid":{"rendered":"https:\/\/kiencang.net\/2013\/08\/23\/3-ham-kiem-tra-gia-tri-cua-bien-trong-php\/"},"modified":"2013-08-23T07:27:00","modified_gmt":"2013-08-23T07:27:00","slug":"3-ham-kiem-tra-gia-tri-cua-bien-trong-php","status":"publish","type":"post","link":"https:\/\/kiencang.net\/3-ham-kiem-tra-gia-tri-cua-bien-trong-php\/","title":{"rendered":"3 h\u00e0m ki\u1ec3m tra gi\u00e1 tr\u1ecb c\u1ee7a bi\u1ebfn trong PHP"},"content":{"rendered":"\n<p>Ki\u1ec3m tra t\u00ednh h\u1ee3p l\u1ec7 c\u1ee7a bi\u1ebfn tr\u01b0\u1edbc khi th\u1ef1c thi l\u00e0 \u0111i\u1ec1u v\u00f4 c\u00f9ng quan tr\u1ecdng, l\u00fd do l\u00e0 v\u00ec b\u1ea1n kh\u00f4ng th\u1ec3 ki\u1ec3m so\u00e1t \u0111\u01b0\u1ee3c ng\u01b0\u1eddi d\u00f9ng s\u1ebd thao t\u00e1c, nh\u1eadp c\u00e1i g\u00ec \u0111\u1ec3 \u0111\u01b0a l\u00ean server x\u1eed l\u00fd.<\/p>\n\n\n\n<p>N\u1ebfu b\u1ea1n kh\u00f4ng ki\u1ec3m tra t\u00ednh h\u1ee3p l\u1ec7, \u0111i\u1ec1u th\u01b0\u1eddng xuy\u00ean x\u1ea3y ra s\u1ebd l\u00e0 x\u1eed l\u00fd b\u1ecb l\u1ed7i, d\u1eef li\u1ec7u kh\u00f4ng h\u1ee3p chu\u1ea9n v\u00e0 t\u1ed1n t\u00e0i nguy\u00ean x\u1eed l\u00fd nh\u1eefng l\u1ec7nh l\u1ed7i \u0111\u00e1ng ra kh\u00f4ng c\u1ea7n ph\u1ea3i th\u1ef1c hi\u1ec7n.<\/p>\n\n\n\n<p>B\u1ea1n c\u1ea7n v\u00ed d\u1ee5 c\u1ee5 th\u1ec3 h\u01a1n? Ch\u00fang ta c\u00f9ng x\u00e9t tr\u01b0\u1eddng h\u1ee3p sau \u0111\u00e2y, b\u1ea1n c\u00f3 ba tr\u01b0\u1eddng c\u1ea7n nh\u1eadp \u0111\u00f3 l\u00e0 h\u1ecd t\u00ean, n\u0103m t\u1ed1t nghi\u1ec7p c\u1ea5p 3 v\u00e0 \u0111\u1ecba ch\u1ec9 email c\u1ee7a ng\u01b0\u1eddi d\u00f9ng \u0111\u0103ng k\u00fd. Gi\u1edd tr\u01b0\u1edbc khi l\u01b0u d\u1eef li\u1ec7u b\u1ea1n c\u1ea7n ph\u1ea3i ki\u1ec3m tra xem c\u00e1c tr\u01b0\u1eddng \u0111\u00e3 \u0111\u01b0\u1ee3c \u0111i\u1ec1n hay ch\u01b0a, c\u00e1i th\u1ee9 hai, n\u0103m t\u1ed1t nghi\u1ec7p c\u1ea5p 3 c\u00f3 ph\u1ea3i l\u00e0 s\u1ed1 kh\u00f4ng? \u0110\u1ecba ch\u1ec9 email \u0111\u00e3 \u0111\u00fang \u0111\u1ecbnh d\u1ea1ng ch\u01b0a hay h\u1ecd \u0111i\u1ec1n <code>ducanhplus@ffff<\/code> c\u0169ng v\u1eabn \u0111\u01b0\u1ee3c l\u01b0u?<\/p>\n\n\n\n<p>Ba h\u00e0m ki\u1ec3m tra gi\u00e1 tr\u1ecb c\u1ee7a bi\u1ebfn:<\/p>\n\n\n\n<ul><li><code>isset($bien)<\/code>: tr\u1ea3 v\u1ec1 gi\u00e1 tr\u1ecb TRUE n\u1ebfu $bien c\u00f3 t\u1ed3n t\u1ea1i v\u00e0 kh\u00f4ng ph\u1ea3i l\u00e0 NULL.<\/li><li><code>empty($bien)<\/code>: tr\u1ea3 v\u1ec1 gi\u00e1 tr\u1ecb TRUE n\u1ebfu $bien ch\u01b0a t\u1ed3n t\u1ea1i, ch\u1ee9a gi\u00e1 tr\u1ecb NULL ho\u1eb7c b\u1ea3n th\u00e2n n\u00f3 l\u00e0 chu\u1ed7i r\u1ed7ng.<\/li><li><code>is_numeric($bien)<\/code>: tr\u1ea3 v\u1ec1 gi\u00e1 tr\u1ecb TRUE n\u1ebfu $bien l\u00e0 m\u1ed9t s\u1ed1 ho\u1eb7c chu\u1ed7i c\u00f3 th\u1ec3 chuy\u1ec3n sang s\u1ed1.<\/li><\/ul>\n","protected":false},"excerpt":{"rendered":"<p>Ki\u1ec3m tra t\u00ednh h\u1ee3p l\u1ec7 c\u1ee7a bi\u1ebfn tr\u01b0\u1edbc khi th\u1ef1c thi l\u00e0 \u0111i\u1ec1u v\u00f4 c\u00f9ng quan tr\u1ecdng, l\u00fd do l\u00e0 v\u00ec b\u1ea1n kh\u00f4ng th\u1ec3 ki\u1ec3m so\u00e1t \u0111\u01b0\u1ee3c ng\u01b0\u1eddi d\u00f9ng s\u1ebd thao t\u00e1c, nh\u1eadp c\u00e1i g\u00ec \u0111\u1ec3 \u0111\u01b0a l\u00ean server x\u1eed l\u00fd. N\u1ebfu b\u1ea1n kh\u00f4ng ki\u1ec3m tra t\u00ednh h\u1ee3p l\u1ec7, \u0111i\u1ec1u th\u01b0\u1eddng xuy\u00ean x\u1ea3y ra s\u1ebd &hellip;<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[238],"tags":[],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v21.6 - https:\/\/yoast.com\/wordpress\/plugins\/seo\/ -->\n<title>3 h\u00e0m ki\u1ec3m tra gi\u00e1 tr\u1ecb c\u1ee7a bi\u1ebfn trong PHP &#8226; Ki\u1ebfn c\u00e0ng<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/kiencang.net\/3-ham-kiem-tra-gia-tri-cua-bien-trong-php\/\" \/>\n<meta property=\"og:locale\" content=\"vi_VN\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"3 h\u00e0m ki\u1ec3m tra gi\u00e1 tr\u1ecb c\u1ee7a bi\u1ebfn trong PHP &#8226; Ki\u1ebfn c\u00e0ng\" \/>\n<meta property=\"og:description\" content=\"Ki\u1ec3m tra t\u00ednh h\u1ee3p l\u1ec7 c\u1ee7a bi\u1ebfn tr\u01b0\u1edbc khi th\u1ef1c thi l\u00e0 \u0111i\u1ec1u v\u00f4 c\u00f9ng quan tr\u1ecdng, l\u00fd do l\u00e0 v\u00ec b\u1ea1n kh\u00f4ng th\u1ec3 ki\u1ec3m so\u00e1t \u0111\u01b0\u1ee3c ng\u01b0\u1eddi d\u00f9ng s\u1ebd thao t\u00e1c, nh\u1eadp c\u00e1i g\u00ec \u0111\u1ec3 \u0111\u01b0a l\u00ean server x\u1eed l\u00fd. N\u1ebfu b\u1ea1n kh\u00f4ng ki\u1ec3m tra t\u00ednh h\u1ee3p l\u1ec7, \u0111i\u1ec1u th\u01b0\u1eddng xuy\u00ean x\u1ea3y ra s\u1ebd &hellip;\" \/>\n<meta property=\"og:url\" content=\"https:\/\/kiencang.net\/3-ham-kiem-tra-gia-tri-cua-bien-trong-php\/\" \/>\n<meta property=\"og:site_name\" content=\"Ki\u1ebfn c\u00e0ng\" \/>\n<meta property=\"article:author\" content=\"https:\/\/www.facebook.com\/anhducnguyen87\/\" \/>\n<meta property=\"article:published_time\" content=\"2013-08-23T07:27:00+00:00\" \/>\n<meta name=\"author\" content=\"Nguy\u1ec5n \u0110\u1ee9c Anh\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:label1\" content=\"\u0110\u01b0\u1ee3c vi\u1ebft b\u1edfi\" \/>\n\t<meta name=\"twitter:data1\" content=\"Nguy\u1ec5n \u0110\u1ee9c Anh\" \/>\n\t<meta name=\"twitter:label2\" content=\"\u01af\u1edbc t\u00ednh th\u1eddi gian \u0111\u1ecdc\" \/>\n\t<meta name=\"twitter:data2\" content=\"2 ph\u00fat\" \/>\n<!-- \/ Yoast SEO plugin. -->","yoast_head_json":{"title":"3 h\u00e0m ki\u1ec3m tra gi\u00e1 tr\u1ecb c\u1ee7a bi\u1ebfn trong PHP &#8226; 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\/3-ham-kiem-tra-gia-tri-cua-bien-trong-php\/","og_locale":"vi_VN","og_type":"article","og_title":"3 h\u00e0m ki\u1ec3m tra gi\u00e1 tr\u1ecb c\u1ee7a bi\u1ebfn trong PHP &#8226; Ki\u1ebfn c\u00e0ng","og_description":"Ki\u1ec3m tra t\u00ednh h\u1ee3p l\u1ec7 c\u1ee7a bi\u1ebfn tr\u01b0\u1edbc khi th\u1ef1c thi l\u00e0 \u0111i\u1ec1u v\u00f4 c\u00f9ng quan tr\u1ecdng, l\u00fd do l\u00e0 v\u00ec b\u1ea1n kh\u00f4ng th\u1ec3 ki\u1ec3m so\u00e1t \u0111\u01b0\u1ee3c ng\u01b0\u1eddi d\u00f9ng s\u1ebd thao t\u00e1c, nh\u1eadp c\u00e1i g\u00ec \u0111\u1ec3 \u0111\u01b0a l\u00ean server x\u1eed l\u00fd. N\u1ebfu b\u1ea1n kh\u00f4ng ki\u1ec3m tra t\u00ednh h\u1ee3p l\u1ec7, \u0111i\u1ec1u th\u01b0\u1eddng xuy\u00ean x\u1ea3y ra s\u1ebd &hellip;","og_url":"https:\/\/kiencang.net\/3-ham-kiem-tra-gia-tri-cua-bien-trong-php\/","og_site_name":"Ki\u1ebfn c\u00e0ng","article_author":"https:\/\/www.facebook.com\/anhducnguyen87\/","article_published_time":"2013-08-23T07:27:00+00:00","author":"Nguy\u1ec5n \u0110\u1ee9c Anh","twitter_card":"summary_large_image","twitter_misc":{"\u0110\u01b0\u1ee3c vi\u1ebft b\u1edfi":"Nguy\u1ec5n \u0110\u1ee9c Anh","\u01af\u1edbc t\u00ednh th\u1eddi gian \u0111\u1ecdc":"2 ph\u00fat"},"schema":{"@context":"https:\/\/schema.org","@graph":[{"@type":"WebPage","@id":"https:\/\/kiencang.net\/3-ham-kiem-tra-gia-tri-cua-bien-trong-php\/","url":"https:\/\/kiencang.net\/3-ham-kiem-tra-gia-tri-cua-bien-trong-php\/","name":"3 h\u00e0m ki\u1ec3m tra gi\u00e1 tr\u1ecb c\u1ee7a bi\u1ebfn trong PHP &#8226; Ki\u1ebfn c\u00e0ng","isPartOf":{"@id":"https:\/\/kiencang.net\/#website"},"datePublished":"2013-08-23T07:27:00+00:00","dateModified":"2013-08-23T07:27:00+00:00","author":{"@id":"https:\/\/kiencang.net\/#\/schema\/person\/5e7e1a04d8d1218ad8c421ba43d25c16"},"breadcrumb":{"@id":"https:\/\/kiencang.net\/3-ham-kiem-tra-gia-tri-cua-bien-trong-php\/#breadcrumb"},"inLanguage":"vi","potentialAction":[{"@type":"ReadAction","target":["https:\/\/kiencang.net\/3-ham-kiem-tra-gia-tri-cua-bien-trong-php\/"]}]},{"@type":"BreadcrumbList","@id":"https:\/\/kiencang.net\/3-ham-kiem-tra-gia-tri-cua-bien-trong-php\/#breadcrumb","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https:\/\/kiencang.net\/"},{"@type":"ListItem","position":2,"name":"3 h\u00e0m ki\u1ec3m tra gi\u00e1 tr\u1ecb c\u1ee7a bi\u1ebfn trong PHP"}]},{"@type":"WebSite","@id":"https:\/\/kiencang.net\/#website","url":"https:\/\/kiencang.net\/","name":"Ki\u1ebfn c\u00e0ng","description":"\u00d4m l\u00fd thuy\u1ebft, h\u00f4n th\u1ef1c h\u00e0nh","potentialAction":[{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https:\/\/kiencang.net\/?s={search_term_string}"},"query-input":"required name=search_term_string"}],"inLanguage":"vi"},{"@type":"Person","@id":"https:\/\/kiencang.net\/#\/schema\/person\/5e7e1a04d8d1218ad8c421ba43d25c16","name":"Nguy\u1ec5n \u0110\u1ee9c Anh","image":{"@type":"ImageObject","inLanguage":"vi","@id":"https:\/\/kiencang.net\/#\/schema\/person\/image\/","url":"https:\/\/secure.gravatar.com\/avatar\/6d71f9b89393952a8382e30dad26c1ec?s=96&d=monsterid&r=g","contentUrl":"https:\/\/secure.gravatar.com\/avatar\/6d71f9b89393952a8382e30dad26c1ec?s=96&d=monsterid&r=g","caption":"Nguy\u1ec5n \u0110\u1ee9c Anh"},"description":"Sinh n\u0103m 1987, t\u1ed1t nghi\u1ec7p Cao \u0111\u1eb3ng th\u1ef1c h\u00e0nh FPT qu\u00e3ng 2014, chuy\u00ean ng\u00e0nh Thi\u1ebft k\u1ebf website. T\u00f4i th\u00edch Content, SEO, Ads, T\u0103ng t\u1ed1c website v\u00e0 Th\u01b0\u01a1ng m\u1ea1i \u0111i\u1ec7n t\u1eed. B\u00ean c\u1ea1nh b\u00e0i t\u1ef1 vi\u1ebft, t\u00f4i c\u0169ng d\u1ecbch nhi\u1ec1u n\u1ed9i dung th\u00fa v\u1ecb c\u1ee7a c\u00e1c t\u00e1c gi\u1ea3 kh\u00e1c nhau. FB c\u00e1 nh\u00e2n: facebook.com\/anhducnguyen87. Email li\u00ean h\u1ec7: guiemailchotoi@gmail.com","sameAs":["https:\/\/www.facebook.com\/anhducnguyen87\/"],"url":"https:\/\/kiencang.net\/author\/admin\/"}]}},"_links":{"self":[{"href":"https:\/\/kiencang.net\/wp-json\/wp\/v2\/posts\/20220"}],"collection":[{"href":"https:\/\/kiencang.net\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/kiencang.net\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/kiencang.net\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/kiencang.net\/wp-json\/wp\/v2\/comments?post=20220"}],"version-history":[{"count":0,"href":"https:\/\/kiencang.net\/wp-json\/wp\/v2\/posts\/20220\/revisions"}],"wp:attachment":[{"href":"https:\/\/kiencang.net\/wp-json\/wp\/v2\/media?parent=20220"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/kiencang.net\/wp-json\/wp\/v2\/categories?post=20220"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/kiencang.net\/wp-json\/wp\/v2\/tags?post=20220"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}