If, after the above modifications, you change the value of the prototype property, the private property values assigned individually do not reflect the prototype change. For example, changing the prototype status property to reflect the company-wide vacation period is accomplished as follows: coworker.
And in fact, the next statement of the teamMember constructor function invokes the member method, passing two of the incoming parameters to the coworker function. But all other pieces of the teamMember object are readily accessible and meaningful to your scripts. An unusual side effect to the connection between these nested objects is that the teamMember objects do not have the coworker constructor in their prototype chain.
Therefore, if you assign a property and value to the prototype of the coworker constructor, none of the teamMember objects gains that property.
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Then you can do something like the following: coworker. And, just like any prototype property or method, you can override the private value for a single instance without disturbing the default values of the other objects. In Mozilla and Opera 9, many of these language capabilities add potentially enormous power to the DOM you use every day. These browsers give scripters access to the constructors of every type of DOM object, thus allowing you to add prototype properties and methods to any class of DOM object. Go crazy! Solution Use the objectsArraysStrings.
The first, object2String , works through the properties of a custom object, and assembles a string in the same format used to generate the object in the curly-braced shortcut syntax. The sole parameter to the function is a reference to the custom object you wish to convert. The returned value is a string, including the curly braces surrounding the text. Each function relies on the other at times.
For example, if you are converting an object to a string, and one of its properties is an array, the array portion is passed through array2String to get the desired format for that segment of the full string. Conversely, converting an array of objects requires calls to object2String to format the object portions. To reconstruct the object or array data type from the string, use one of the final two functions that applies to the outermost construction of the string.
The two functions perform the same operation, but the names are provided for each conversion type to improve readability of the code that invokes them. Despite warnings elsewhere in this book about performance degradation of the eval function, its use is necessary here. Let the type of the outermost data structure govern which of the two convert-tostring functions you use.
For example, if you define an object that contains three properties and two methods, the only name that is accessible to other script statements outside of the object is the identifier you use for the entire object. The five names you use for the properties and methods can be used anywhere else without fear of naming conflicts. Access to the internal properties and methods is via the standard objectName.
Discussion At issue here is the global i.
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On another front, scripters without formal programming training tend to be rather loose in their attention to detail in the error department—something that can come back to bite you. On the other hand, the browser implementations of some of the details of exception handling are far from compatible. This chapter ends with some suggestions about improving script performance.
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COMS 1001: Introduction to Computers (Spring 2006)
Not only is a global variable accessible by all script statements in the current window or frame, but statements in other frames or windows served from the same domain and server can access those global variables by way of the window or frame reference. For example, a statement in a menu frame can reference a global variable named myVar in a frame named content as follows: parent.
Where you must exercise care is in defining a new variable inside a function with the var keyword. If you fail to use the keyword inside the function, the variable is treated as a global variable. Even though the keyword is optional for global variable declarations, it is good coding style to use var for globals as well. That way you can readily see where a variable is first used in a script. But in any case, this situation definitely calls for declaring the variables outside of the loops for another reason.