JavaScrip E\u011fitimimizin bu b\u00f6l\u00fcm\u00fcnde JavaScript de\u011fi\u015fkenleri(JavaScript Variables) nas\u0131l tan\u0131mlan\u0131r? bunu \u00f6\u011frenece\u011fiz. JavaScript Programlama dilinde “var” anahtar s\u00f6zc\u00fc\u011f\u00fc ile bir JavaScript de\u011fi\u015fkeni olu\u015fturaca\u011f\u0131m\u0131z\u0131 bildiririz. \u00d6rne\u011fin: “var firstName;” tan\u0131mlamas\u0131 JavaScript dilinde hi\u00e7 bir de\u011fer atamas\u0131 ger\u00e7ekle\u015ftirilmemi\u015f “firstName” ad\u0131nda bir de\u011fi\u015fken tan\u0131mlamas\u0131d\u0131r. <\/p>\n\n\n\n
A\u015fa\u011f\u0131daki \u00f6rne\u011fi inceleyerek Javascript de\u011fi\u015fken tan\u0131mlamas\u0131n\u0131 detayl\u0131 inceleyelim ve genel kurallar\u0131m\u0131zdan bahsedelim. <\/p>\n\n\n\n
<script>\n var x = 2; \n var y = 3; \n var z = x + y; \n console.log(z); \n<\/script><\/code><\/pre>\n\n\n\n- Bu \u00f6rnekte, x, y ve z de\u011fi\u015fkenlerdir: (Atama operat\u00f6rleri sonraki derslerde detayl\u0131 anlat\u0131lacakt\u0131r.)<\/li>
- x de\u011fi\u015fkenine 2 de\u011feri atanm\u0131\u015ft\u0131r.<\/li>
- y de\u011fi\u015fkenine 3 de\u011feri atanm\u0131\u015ft\u0131r.<\/li>
- x ve ye de\u011ferleri toplanarak z = 5 de\u011ferine sahip olacakt\u0131r.<\/li>
- console.log ile taray\u0131c\u0131 \u00fczerinde yazd\u0131rma i\u015flemi ger\u00e7ekle\u015ftirildi.<\/li><\/ul>\n\n\n\n
String bir de\u011fi\u015fken de tan\u0131mlayabilirsiniz. A\u015fa\u011f\u0131daki \u00f6rnekte bunun bir \u00f6rne\u011fi verilmi\u015ftir.<\/p>\n\n\n\n
<script> \n var text1 = \"String de\u011fer i\u00e7eri\u011fi.\"; \n console.log(text1);\n<\/script>\n<\/code><\/pre>\n\n\n\nDe\u011fer atamas\u0131 yap\u0131lmayan bir de\u011fi\u015fkeni yazd\u0131rmaya \u00e7al\u0131\u015f\u0131rsan\u0131z “Undefined” d\u00f6n\u00fc\u015f\u00fcn\u00fc al\u0131rs\u0131n\u0131z. \u00d6rnek:<\/p>\n\n\n\n
<script> \n var firstName;\n console.log(firstName); \/* Undefined - tan\u0131mlanmam\u0131\u015f. *\/\n<\/script>\n\n<\/code><\/pre>\n\n\n\nAyn\u0131 de\u011fi\u015fkenin tekrar tan\u0131mlanmas\u0131 durumunda son tan\u0131mlanan de\u011fi\u015fkene de\u011fer atamas\u0131 yap\u0131lmazsa 1. durumda atanm\u0131\u015f de\u011fer ge\u00e7erli ge\u00e7erli olur. e\u011fer yeni de\u011fer atamas\u0131 yap\u0131l\u0131rsa yeni de\u011fer ge\u00e7erli olur.’ \u00d6rnek: <\/p>\n\n\n\n
<script> \n var lastName = \"Ko\u00e7\";\n var lastName; \/\/ yeni de\u011fer atamas\u0131 yap\u0131lmad\u0131\u011f\u0131 i\u00e7in ekranda Ko\u00e7 yazar.\n console.log(lastName);\n<\/script>\n<\/code><\/pre>\n\n\n\n<\/p>\n\n\n\n
De\u011fi\u015fkenler adlar olu\u015fturmak i\u00e7in genel kurallar (benzersiz tan\u0131mlay\u0131c\u0131lar):<\/h2>\n\n\n\n
De\u011fi\u015fken tan\u0131mlamalar\u0131n\u0131 yaparken dikkat etmemiz gereken baz\u0131 kurallar vard\u0131r. A\u015fa\u011f\u0131daki maddelerde genel kurallar\u0131 tan\u0131mlayal\u0131m.<\/p>\n\n\n\n
- \u0130simler harf, rakam, alt \u00e7izgi ve dolar i\u015fareti i\u00e7erebilir.<\/li>
- \u0130simler bir harfle ba\u015flamal\u0131d\u0131r rakam veya say\u0131 ile ba\u015flamamal\u0131d\u0131r<\/li>
- \u0130simler de $ ve _ ile ba\u015flayabilir <\/li>
- \u0130simler b\u00fcy\u00fck \/ k\u00fc\u00e7\u00fck harfe duyarl\u0131d\u0131r (y ve Y farkl\u0131 de\u011fi\u015fkenlerdir)<\/li>
- Ayr\u0131lm\u0131\u015f kelimeler (JavaScript anahtar kelimeleri gibi) ad olarak kullan\u0131lamaz<\/li>
- De\u011fi\u015fkeni bildirirken ayr\u0131ca bir de\u011fer atayabilirsiniz:<\/li><\/ul>\n\n\n\n
<\/p>\n","protected":false},"excerpt":{"rendered":"
JavaScrip E\u011fitimimizin bu b\u00f6l\u00fcm\u00fcnde JavaScript de\u011fi\u015fkenleri(JavaScript Variables) nas\u0131l tan\u0131mlan\u0131r? bunu \u00f6\u011frenece\u011fiz. JavaScript Programlama dilinde “var” anahtar s\u00f6zc\u00fc\u011f\u00fc ile bir JavaScript de\u011fi\u015fkeni olu\u015fturaca\u011f\u0131m\u0131z\u0131 bildiririz. \u00d6rne\u011fin: “var firstName;” tan\u0131mlamas\u0131 JavaScript dilinde hi\u00e7 bir de\u011fer atamas\u0131 ger\u00e7ekle\u015ftirilmemi\u015f “firstName” ad\u0131nda bir de\u011fi\u015fken tan\u0131mlamas\u0131d\u0131r. A\u015fa\u011f\u0131daki \u00f6rne\u011fi inceleyerek Javascript de\u011fi\u015fken tan\u0131mlamas\u0131n\u0131 detayl\u0131 inceleyelim ve genel kurallar\u0131m\u0131zdan bahsedelim. Bu \u00f6rnekte, x, y […]<\/p>\n","protected":false},"author":1,"featured_media":6338,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"tdm_status":"","tdm_grid_status":""},"categories":[3388,24],"tags":[3484,424,3411,3483],"_links":{"self":[{"href":"https:\/\/www.kampuskod.com\/wp-json\/wp\/v2\/posts\/6337"}],"collection":[{"href":"https:\/\/www.kampuskod.com\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.kampuskod.com\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.kampuskod.com\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.kampuskod.com\/wp-json\/wp\/v2\/comments?post=6337"}],"version-history":[{"count":3,"href":"https:\/\/www.kampuskod.com\/wp-json\/wp\/v2\/posts\/6337\/revisions"}],"predecessor-version":[{"id":6516,"href":"https:\/\/www.kampuskod.com\/wp-json\/wp\/v2\/posts\/6337\/revisions\/6516"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.kampuskod.com\/wp-json\/wp\/v2\/media\/6338"}],"wp:attachment":[{"href":"https:\/\/www.kampuskod.com\/wp-json\/wp\/v2\/media?parent=6337"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.kampuskod.com\/wp-json\/wp\/v2\/categories?post=6337"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.kampuskod.com\/wp-json\/wp\/v2\/tags?post=6337"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}