AJAX and PHP

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AJAX Suggest and Autocomplete Next, we will talk about the handleKeyUp function. This is the function used for navigation through the results and submission. Since we are interested only in few keys, the others are ignored. Before getting there we need to make sure the code works on every browser. In order for this to happen, we need to write a few lines as we can see for ourselves. In order to know which characters to consider, we need to know the codes of the keys. The event object received as parameter has a property keyCode that has the code of the pressed key. In the following table, you can find a list of most of the special keys: Table 1: Key codes Key Code Key Code Backspace 8 Print Screen 44 Tab 9 Delete 46 Enter 13 F1 112 Shift 16 F2 113 Ctrl 17 F3 114 Alt 18 F4 115 Pause/Break 19 F5 116 Caps Lock 20 F6 117 Esc 27 F7 118 Page Up 33 F8 119 Page Down 34 F9 120 End 35 F10 121 Home 36 F11 122 Left Arrow 37 F12 123 Up Arrow 38 Right Arrow 39 Down Arrow 40 On pressing Enter (code 13), the page submits to the php.net help with the specification for the currently selected suggestion if any is selected. On pressing the up or down arrow keys the currently selected suggestion moves one position up or down if possible. The current keyword is also updated with the value of the current selected suggestion. We do not handle any other pressed keys since they modify the keyword and we have already presented the checkForChanges function that handles this part. Another problem that arises when having more than ten suggestions available is that we have a scrollable div region. As we stated before, we want the user to be able to navigate through the results by using the up and down arrow keys. If the user reaches a result that is not currently 186 www.it-ebooks.info
Chapter 6 visible, we need to scroll in the region in order to make that result visible. In order to implement this, we keep minimum and maximum positions of the results that are currently visible. It's as if we had a window that moves through the results according to the arrows' movements and the current selected result. The selectRange and autocompleteKeyword functions do the trick for the type-ahead look by autocompleting the current keyword with the rest of the missing letters up to the first suggestion. The part that is missing is added as highlighted text to the current keyword. The select() method selects all the text, and hence selecting only a part of a text is not possible. In order to do this, Internet Explorer offers one solution while Mozilla / Firefox offers another one. It is not for the first time that issues are not the same in all browsers, so we have to take each case and solve it separately. In Firefox, issues are simple because there is just one function that does all the work for us—setSelectionRange. This function takes two parameters—the start position of the selection and the length of the selection. In Internet Explorer, we have to use the TextRange object in order to achieve the same goal. Let us take a closer look at it because it might be useful for us in the future and for this, we need to know what it can do. The TextRange object can carry out tasks such as searching or selecting text. Text ranges let you pick out characters, words, and sentences from the text. Each of these three is a logical unit of the object. In order to use such an object you have to follow these steps: • Create the text range • Apply a method to the selected text You can copy the text, search in the text, and select a part of the text, as in our case. To create such an object you can call the createTextRange method on a body, textarea, or button element. Each object has a start and an end position defining the scope of the text. When you create a new text range, the start and end positions contain the entire content by default. To modify the scope of the text range we can use the move, moveStart, and moveEnd functions. Each of them takes two parameters—the first parameter specifies the logical unit and the second one the number of units to move. The result contains the numbers of units moved. The select method makes the selection equal to the current object. In order to have a complete view of its capabilities check the following link on MSDN: http://msdn.microsoft.com/library/default.asp?url=/workshop/ author/dyncontent/textrange.asp. After receiving the suggestions and inserting them into the page, we need to autocomplete the keyword with the value of the first suggestion. This is accomplished by using the selectRange function described above. For the error-handling part, we use the displayError function that displays an alert with the error message as parameter. OK, now we have seen how it goes for the client side of the application. Let's check the server side. For the server side, things are very simple. The suggest.php file retrieves the parameter passed by the client and that represents the searched for keyword. Then it calls a method of the Suggest class 187 www.it-ebooks.info
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AJAX and PHP Building Responsive We
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About the Authors Cristian Darie is
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About the Reviewers Emilian Balanes
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Table of Contents Preface 1 Chapter
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Table of Contents Chapter 6: AJAX S
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Preface AJAX is a complex phenomeno
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Preface What You Need for This Book
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Preface Errata Although we have tak
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1 AJAX and the Future of Web Applic
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Chapter 1 Because end-user satisfac
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Chapter 1 Three points for you to k
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Chapter 1 With JavaScript, develope
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interrupting the user from his or h
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• Creating simple online chat sol
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Chapter 1 done typing. (This method
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Chapter 1 All exercises from this b
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etrieve the user name $name = $_GET
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Chapter 1 If you're curious to test
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Chapter 1 request. In our case, thi
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2 Client-Side Techniques with Smart
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AJAX Foundations: JavaScript and
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Chapter 2 • Because there is no s
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Time for Action—Using JavaScript
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Even More DOM In the previous exerc
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Chapter 2 What Just Happened? Well,
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Chapter 2 font-size: 10pt; } .Table
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Chapter 2 Creating the XMLHttpReque
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Chapter 2 You could, for example, c
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You will learn the most interesting
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Chapter 2 The safer version of proc
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Chapter 2 4. Create a file call
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Chapter 2 Figure 2.6: The Four HTTP
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Chapter 2 } } else { // display sta
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Chapter 2 } { // try to create XMLH
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Chapter 2 The responseXML method of
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Chapter 2 Figure 2.10: Opera Displa
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I admit that the following piece of
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3 Server-Side Techniques with PHP a
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Chapter 3 } for (var i=0; i
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Chapter 3 // create the element $b
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Chapter 3 // create the root eleme
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Chapter 3 // read a file from the s
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Chapter 3 Figure 3.3: PHP Parameter
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Chapter 3 Without the customized er
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} } // display the error in case of
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Chapter 3 Figure 3.7: Connecting to
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Chapter 3 } } // continue only if H
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Chapter 3 You can make Firefox list
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Chapter 3 } "MSXML2.XMLHTTP.4.0", "
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'TEXT: ' . $errStr . chr(10) . 'LOC
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etrieve the parameters $num = 1; //
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Chapter 3 Figure 3.16: Flowchart De
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} Chapter 3 // only continue if xml
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} throw(response.length == 0 ? "Ser
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function process() { // ... if (req
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Chapter 3 Working with MySQL A back
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Chapter 3 Figure 3.17: Executing SQ
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Chapter 3 SELECT user_id, user_name
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3. In your foundations folder, crea
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Chapter 3 After these commands exec
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Chapter 3 • friendly.php is a PHP
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This example requires a JavaSc
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} } // try to connect to the server
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Chapter 3 } // create HTML-formatte
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Chapter 3 On the server side, all t
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4 AJAX Form Validation Validating i
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Chapter 4 Always validate user inpu
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Chapter 4 Figure 4.4: Successful Su
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Chapter 4 .left { margin-left: 150p
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Chapter 4 value="" />
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Registration Successfull! <<
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Chapter 4 } } { // display error me
Page 147 and 148: Chapter 4 require_once ('config.php
Page 149 and 150: Chapter 4 } { } $_POST['txtBthDay']
Page 151 and 152: Chapter 4 } } ?> return ($value ==
Page 153 and 154: Chapter 4 The field ID and value re
Page 155 and 156: Chapter 4 If we are dealing with cl
Page 157 and 158: 5 AJAX Chat We are living in a worl
Page 159 and 160: Chapter 5 Implementing AJAX Chat We
Page 161 and 162: Chapter 5 // default the last id to
Page 163 and 164: } Chapter 5 ' DATE_FORMAT(posted_on
Page 165 and 166: Chapter 5 AJAX Chat Your b
Page 167 and 168: * function called when the Send but
Page 169 and 170: } } // retrieve the arrays from the
Page 171 and 172: Chapter 5 } } } // call server asyn
Page 173 and 174: Chapter 5 If you analyze the code f
Page 175 and 176: The business logic behind chat.php
Page 177 and 178: 6 AJAX Suggest and Autocomplete Sug
Page 179 and 180: Chapter 6 The clever part of the Ja
Page 181 and 182: Chapter 6 6. Create another file na
Page 183 and 184: Chapter 6 { } a { } font-weight: bo
Page 185 and 186: Chapter 6 } { // try to create XMLH
Page 187 and 188: Chapter 6 } } } } { } displayError(
Page 189 and 190: Chapter 6 div += "" + "" + crtFunct
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Page 193 and 194: Chapter 6 } } else // FF if (oText.
Page 195 and 196: Chapter 6 Figure 6.4: PHP Documenta
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Page 201 and 202: 7 AJAX Real-Time Charting with SVG
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Page 205 and 206: Chapter 7 Figure 7.2: SVG Charting
Page 207 and 208: Chapter 7 } { xmlHttp.onreadystatec
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Page 211 and 212: Chapter 7 } // Supported by Mozilla
Page 213 and 214: Chapter 7 • All HTTP requests go
Page 215 and 216: 8 AJAX Grid Data grids have always
Page 217 and 218: Chapter 8 Figure 8.2: AJAX Grid in
Page 219 and 220: $name = $_GET['name']; // update th
Page 221 and 222: } Chapter 8 if (!isset($_SESSION['r
Page 223 and 224: Chapter 8 # editId(, true) Edit
Page 225 and 226: Chapter 8 } // this should work for
Page 227 and 228: } Chapter 8 if(editableId) editId(e
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Page 231 and 232: Chapter 8 On the client, this data
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Page 235 and 236: 9 AJAX RSS Reader In the last few y
Page 237 and 238: Chapter 9 Figure 9.1: Managing RSS
Page 239 and 240: header('Pragma: no-cache'); header(
Page 241 and 242: Chapter 9 Loading feed... Abou
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Page 245 and 246: Chapter 9 } width: 410px; backgroun
Page 247 and 248: And finally, we send the HTTP reque
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10 AJAX Drag and Drop When drag-and
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Chapter 10 The Prototype features a
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Chapter 10 When dropping a task on
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Chapter 10 DROP HERE TO DELETE
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header('Expires: Fri, 25 Dec 1980 0
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Chapter 10 } } } else if (action ==
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Chapter 10 11. Load http://localhos
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details are saved using a cache sys
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Chapter 10 Summary This is it! You'
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A Preparing Your Working Environmen
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Appendix A During installation you'
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Before going through any case studi
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Appendix A Preparing Your *nix Play
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8. Finally, point your web browser
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2. Write ajax in the Create a new d
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Index A abort() method, XMLHttpRequ
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exception handling, JavaScript, 43
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PHP Parameters and Error Handling r
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updateChart() function, realTimeCha
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