topical media & game development
professional-ajax-07-Autosuggest-Example-autosuggest.js / js
An autosuggest textbox control.
@class
@scope public
function AutoSuggestControl(oTextbox /*:HTMLInputElement*/,
oProvider /*:SuggestionProvider*/) {
The currently selected suggestions.
@scope private
this.cur /*:int*/ = -1;
The dropdown list layer.
@scope private
this.layer = null;
Suggestion provider for the autosuggest feature.
@scope private.
this.provider /*:SuggestionProvider*/ = oProvider;
The textbox to capture.
@scope private
this.textbox /*:HTMLInputElement*/ = oTextbox;
Timeout ID for fast typers.
@scope private
this.timeoutId /*:int*/ = null;
The text that the user typed.
@scope private
this.userText /*:String*/ = oTextbox.value;
//initialize the control
this.init();
}
Autosuggests one or more suggestions for what the user has typed.
If no suggestions are passed in, then no autosuggest occurs.
@scope private
parameter: aSuggestions An array of suggestion strings.
parameter: bTypeAhead If the control should provide a type ahead suggestion.
AutoSuggestControl.prototype.autosuggest = function (aSuggestions /*:Array*/,
bTypeAhead /*:boolean*/) {
//re-initialize pointer to current suggestion
this.cur = -1;
//make sure there's at least one suggestion
if (aSuggestions.length > 0) {
if (bTypeAhead) {
this.typeAhead(aSuggestions[0]);
}
this.showSuggestions(aSuggestions);
} else {
this.hideSuggestions();
}
};
Creates the dropdown layer to display multiple suggestions.
@scope private
AutoSuggestControl.prototype.createDropDown = function () {
//create the layer and assign styles
this.layer = document.createElement("div");
this.layer.className = "suggestions";
this.layer.style.visibility = "hidden";
this.layer.style.width = this.textbox.offsetWidth;
document.body.appendChild(this.layer);
//when the user clicks on the a suggestion, get the text (innerHTML)
//and place it into a textbox
var oThis = this;
this.layer.onmousedown =
this.layer.onmouseup =
this.layer.onmouseover = function (oEvent) {
oEvent = oEvent || window.event;
oTarget = oEvent.target || oEvent.srcElement;
if (oEvent.type == "mousedown") {
oThis.textbox.value = oTarget.firstChild.nodeValue;
oThis.hideSuggestions();
} else if (oEvent.type == "mouseover") {
oThis.highlightSuggestion(oTarget);
} else {
oThis.textbox.focus();
}
};
};
Gets the left coordinate of the textbox.
@scope private
returns: The left coordinate of the textbox in pixels.
AutoSuggestControl.prototype.getLeft = function () /*:int*/ {
var oNode = this.textbox;
var iLeft = 0;
while(oNode.tagName != "BODY") {
iLeft += oNode.offsetLeft;
oNode = oNode.offsetParent;
}
return iLeft;
};
Gets the top coordinate of the textbox.
@scope private
returns: The top coordinate of the textbox in pixels.
AutoSuggestControl.prototype.getTop = function () /*:int*/ {
var oNode = this.textbox;
var iTop = 0;
while(oNode.tagName != "BODY") {
iTop += oNode.offsetTop;
oNode = oNode.offsetParent;
}
return iTop;
};
Highlights the next or previous suggestion in the dropdown and
places the suggestion into the textbox.
parameter: iDiff Either a positive or negative number indicating whether
to select the next or previous sugggestion, respectively.
@scope private
AutoSuggestControl.prototype.goToSuggestion = function (iDiff /*:int*/) {
var cSuggestionNodes = this.layer.childNodes;
if (cSuggestionNodes.length > 0) {
var oNode = null;
if (iDiff > 0) {
if (this.cur < cSuggestionNodes.length-1) {
oNode = cSuggestionNodes[++this.cur];
}
} else {
if (this.cur > 0) {
oNode = cSuggestionNodes[--this.cur];
}
}
if (oNode) {
this.highlightSuggestion(oNode);
this.textbox.value = oNode.firstChild.nodeValue;
}
}
};
Handles three keydown events.
@scope private
parameter: oEvent The event object for the keydown event.
AutoSuggestControl.prototype.handleKeyDown = function (oEvent /*:Event*/) {
switch(oEvent.keyCode) {
case 38: //up arrow
this.goToSuggestion(-1);
break;
case 40: //down arrow
this.goToSuggestion(1);
break;
case 27: //esc
this.textbox.value = this.userText;
this.selectRange(this.userText.length, 0);
/* falls through */
case 13: //enter
this.hideSuggestions();
oEvent.returnValue = false;
if (oEvent.preventDefault) {
oEvent.preventDefault();
}
break;
}
};
Handles keyup events.
@scope private
parameter: oEvent The event object for the keyup event.
AutoSuggestControl.prototype.handleKeyUp = function (oEvent /*:Event*/) {
var iKeyCode = oEvent.keyCode;
var oThis = this;
//get the currently entered text
this.userText = this.textbox.value;
clearTimeout(this.timeoutId);
//for backspace (8) and delete (46), shows suggestions without typeahead
if (iKeyCode == 8 || iKeyCode == 46) {
this.timeoutId = setTimeout( function () {
oThis.provider.requestSuggestions(oThis, false);
}, 250);
//make sure not to interfere with non-character keys
} else if (iKeyCode < 32 || (iKeyCode >= 33 && iKeyCode < 46) || (iKeyCode >= 112 && iKeyCode <= 123)) {
//ignore
} else {
//request suggestions from the suggestion provider with typeahead
this.timeoutId = setTimeout( function () {
oThis.provider.requestSuggestions(oThis, true);
}, 250);
}
};
Hides the suggestion dropdown.
@scope private
AutoSuggestControl.prototype.hideSuggestions = function () {
this.layer.style.visibility = "hidden";
};
Highlights the given node in the suggestions dropdown.
@scope private
parameter: oSuggestionNode The node representing a suggestion in the dropdown.
AutoSuggestControl.prototype.highlightSuggestion = function (oSuggestionNode) {
for (var i=0; i < this.layer.childNodes.length; i++) {
var oNode = this.layer.childNodes[i];
if (oNode == oSuggestionNode) {
oNode.className = "current"
} else if (oNode.className == "current") {
oNode.className = "";
}
}
};
Initializes the textbox with event handlers for
auto suggest functionality.
@scope private
AutoSuggestControl.prototype.init = function () {
//save a reference to this object
var oThis = this;
//assign the onkeyup event handler
this.textbox.onkeyup = function (oEvent) {
//check for the proper location of the event object
if (!oEvent) {
oEvent = window.event;
}
//call the handleKeyUp() method with the event object
oThis.handleKeyUp(oEvent);
};
//assign onkeydown event handler
this.textbox.onkeydown = function (oEvent) {
//check for the proper location of the event object
if (!oEvent) {
oEvent = window.event;
}
//call the handleKeyDown() method with the event object
oThis.handleKeyDown(oEvent);
};
//assign onblur event handler (hides suggestions)
this.textbox.onblur = function () {
oThis.hideSuggestions();
};
//create the suggestions dropdown
this.createDropDown();
};
Selects a range of text in the textbox.
@scope public
parameter: iStart The start index (base 0) of the selection.
parameter: iEnd The end index of the selection.
AutoSuggestControl.prototype.selectRange = function (iStart /*:int*/, iEnd /*:int*/) {
//use text ranges for Internet Explorer
if (this.textbox.createTextRange) {
var oRange = this.textbox.createTextRange();
oRange.moveStart("character", iStart);
oRange.moveEnd("character", iEnd - this.textbox.value.length);
oRange.select();
//use setSelectionRange() for Mozilla
} else if (this.textbox.setSelectionRange) {
this.textbox.setSelectionRange(iStart, iEnd);
}
//set focus back to the textbox
this.textbox.focus();
};
Builds the suggestion layer contents, moves it into position,
and displays the layer.
@scope private
parameter: aSuggestions An array of suggestions for the control.
AutoSuggestControl.prototype.showSuggestions = function (aSuggestions /*:Array*/) {
var oDiv = null;
this.layer.innerHTML = ""; //clear contents of the layer
for (var i=0; i < aSuggestions.length; i++) {
oDiv = document.createElement("div");
oDiv.appendChild(document.createTextNode(aSuggestions[i]));
this.layer.appendChild(oDiv);
}
this.layer.style.left = this.getLeft() + "px";
this.layer.style.top = (this.getTop()+this.textbox.offsetHeight) + "px";
this.layer.style.visibility = "visible";
};
Inserts a suggestion into the textbox, highlighting the
suggested part of the text.
@scope private
parameter: sSuggestion The suggestion for the textbox.
AutoSuggestControl.prototype.typeAhead = function (sSuggestion /*:String*/) {
//check for support of typeahead functionality
if (this.textbox.createTextRange || this.textbox.setSelectionRange){
var iLen = this.textbox.value.length;
this.textbox.value = sSuggestion;
this.selectRange(iLen, sSuggestion.length);
}
};
Provides suggestions for state/province names.
@class
@scope public
function SuggestionProvider() {
this.http = zXmlHttp.createRequest();
}
Request suggestions for the given autosuggest control.
@scope protected
parameter: oAutoSuggestControl The autosuggest control to provide suggestions for.
SuggestionProvider.prototype.requestSuggestions = function (oAutoSuggestControl /*:AutoSuggestControl*/,
bTypeAhead /*:boolean*/) {
var oHttp = this.http;
//cancel any active requests
if (oHttp.readyState != 0) {
oHttp.abort();
}
//define the data
var oData = {
requesting: "StatesAndProvinces",
text: oAutoSuggestControl.userText,
limit: 5
};
//open connection to server
oHttp.open("post", <suggestions.php>, true);
oHttp.onreadystatechange = function () {
if (oHttp.readyState == 4) {
//evaluate the returned text JavaScript (an array)
var aSuggestions = JSON.parse(oHttp.responseText);
//provide suggestions to the control
oAutoSuggestControl.autosuggest(aSuggestions, bTypeAhead);
}
};
//send the request
oHttp.send(JSON.stringify(oData));
};
(C) Æliens
20/2/2008
You may not copy or print any of this material without explicit permission of the author or the publisher.
In case of other copyright issues, contact the author.
