Tutorial CSS for when JavaScript is Enabled

by in , 0 

document.documentElement.className = "js"

This adds a class to the root <html>, so you could (for example) do something like hide a <div> only when JavaScript is enabled.

.js div#id { display: none; }

Tutorial Cookie Getter/Setter

by in , 0 

/**
 * Gets or sets cookies
 * @param name
 * @param value (null to delete or undefined to get)
 * @param options (domain, expire (in days))
 * @return value or true
 */
_.cookie = function(name, value, options)
{
    if (typeof value === "undefined") {
        var n, v,
            cookies = document.cookie.split(";");
        for (var i = 0; i < cookies.length; i++) {
            n = $.trim(cookies[i].substr(0,cookies[i].indexOf("=")));
            v = cookies[i].substr(cookies[i].indexOf("=")+1);
            if (n === name){
                return unescape(v);
            }
        }
    } else {
        options = options || {};
        if (!value) {
            value = "";
            options.expires = -365;
        } else {
            value = escape(value);
        }
        if (options.expires) {
            var d = new Date();
            d.setDate(d.getDate() + options.expires);
            value += "; expires=" + d.toUTCString();
        }
        if (options.domain) {
            value += "; domain=" + options.domain;
        }
        if (options.path) {
            value += "; path=" + options.path;
        }
        document.cookie = name + "=" + value;
    }
};

Reference URL

Tutorial Comments in JavaScript

by in , 0 

function doSomething() {

    /*
           This code by Chris Coyier
    */

    var i = 0;    // counter to be used later;

}

Comments in JavaScript can be between /* */ markings (useful for multiple line comments) or after // markings (for single lines only).

Tutorial Clear Field on Focus

by in , 0 

<input type="text" onfocus="if(this.value == 'value') { this.value = ''; }" value="value" />

Replace "value" with the default value. If the field is selected, the default value will go away. If the user has previously changed the field value, it'll be left alone.

Alternatively, use onfocus="this.value='';" to always clear the field.

Tutorial Check if Number is Even/Odd

by in , 0 

function isEven(value) {
	if (value%2 == 0)
		return true;
	else
		return false;
}

Tutorial Check if Function Exists Before Calling

by in , 0

When using scripts that are shared between different areas of a site, there may be cases where a function is called that doesn't exist. It makes sense on one page (the dependency is there) but not another. The difference is too slight to warrant forking the file into different versions. Instead, you can just check if the function exists before calling it to avoid the error:

if (typeof yourFunctionName == 'function') { 
  yourFunctionName(); 
}

Tutorial Check if font-family is Honored

by in , 0 

function checkFont(strFamily) {
  var objDiv = document.createElement('div');

  objDiv.style.fontFamily = strFamily;
  objDiv.appendChild(document.createTextNode('FONT TEST'));

  if (window.getComputedStyle) {
      return window.getComputedStyle(objDiv, null).getPropertyValue('font-family') === strFamily;
  }

  return objDiv.currentStyle.fontFamily === strFamily;
}

Usage

var iconFontHonored = checkFont('icomoon');

Reference URL