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About the <head>
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About CSS Preprocessors
CSS preprocessors help make authoring CSS easier. All of them offer things like variables and mixins to provide convenient abstractions.
It's a common practice to apply CSS to a page that styles elements such that they are consistent across all browsers. We offer two of the most popular choices: normalize.css and a reset. Or, choose Neither and nothing will be applied.
About Vendor Prefixing
To get the best cross-browser support, it is a common practice to apply vendor prefixes to CSS properties and values that require them to work. For instance -webkit- or -moz-.
We offer two popular choices: Autoprefixer (which processes your CSS server-side) and -prefix-free (which applies prefixes via a script, client-side).
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If the script you link to has the file extension of a preprocessor, we'll attempt to process it before applying.
var kisi = new Object();
kisi.ad = "Semih";
kisi.yas = "22";
kisi.telefon = "555 0234";
kontrol = ("telefon" in kisi) ?
"Telefon özelliği kişi nesnesinde vardır." :
"Telefon özelliği kişi nesnesinde yoktur.";
document.getElementById("pt_uyari").innerHTML = kontrol;