Tuesday, April 20, 2010

EnsureMinimumNumberOfRows

Here I present a useful function called "EnsureMinimumNumberOfRows".

This function operates on a table and effectively clones the last row in the table a given number of times to ensure that a minimum number of rows exist within the table. it does not clone the contetns of the cells, but rather the nodes themselves and their classnames (by way of cloneNode(false).


////////////////////////////////////////////////////////////////////////////////
// EnsureMinimumNumberOfRows(element, params) - ensures a table will have a minimum
// ========================================== number of visible rows.
// Supported params are:
// numberOfRows - gives the minimum number of rows that will appear
// rowHeight - height, in pixels for added rows
// *NOTE: Does not support empty tables
////////////////////////////////////////////////////////////////////////////////
function EnsureMinimumNumberOfRows(element, params) {
var minimumNumberOfRows = params.numberOfRows || 10, // default minimumNumberOfRows is 10
rowHeight = params.rowHeight || 30, // default rowHeight (for new rows) is 30px
oTable = $(element).select('div.resultList table')[0], // Get the first element as $(element).select returns an array
numberOfRowsToInsert = minimumNumberOfRows - oTable.rows.length + 1;

if (numberOfRowsToInsert > 0) {
var clonedRow = oTable.rows[ oTable.rows.length - 1 ]
clonedCells = clonedRow.getElementsByTagName('td');
for (var i=0;i<numberOfRowsToInsert;i++) {
var oRow = document.createElement("TR");
for (j=0;j<clonedCells.length;j++) {
var oCell = clonedCells[j].cloneNode(false);
oCell.style.height = rowHeight + "px";
oCell.appendChild( document.createTextNode("\u00a0") );
oRow.appendChild(oCell);
}
oTable.appendChild( oRow );
}
}
}

Shannon Norrell


Now posted on GitHub

Wednesday, April 7, 2010

addClassName and removeClassName

Useful CSS Class handling functions.

Here I present addClassName, hasClass and removeClassName and also my old implementation of Array.indexOf. Since this is built into JS these days, you probably won't need it.

addClassName and removeClassName are useful functions because you can pass in space separated classNames and it will add/remove them all.


////////////////////////////////////////////////////////////////////////////////
//
// addClassName([object|string] oHTMLElement, string classNameToAdd)
// Adds classNameToAdd to an HTMLElement. Guaranteed not to add the same className twice.
// classNameToAdd can be a space separated list of classNames.
// You can pass in the id to an object or the actual object
//
////////////////////////////////////////////////////////////////////////////////
function addClassName(oHTMLElement, classNameToAdd) {
if (typeof(oHTMLElement)=="string") { oHTMLElement = document.getElementById(oHTMLElement); }
if (oHTMLElement) {
var theClassName = oHTMLElement.className;
if (theClassName && (theClassName.length > 0)) { // If oHTMLElement already has a class name, some more work is needed
var classNamesToAdd = classNameToAdd.split(" ");
if (classNamesToAdd.length===1 && ((" " + theClassName + " ").lastIndexOf(" " + classNameToAdd + " ") === -1) ) { // If we only have one className to potentially add, take the "less work" approach
oHTMLElement.className = oHTMLElement.className + " " + classNameToAdd;
} else {
var theClassNames = theClassName.split(" "),
iEnd = classNamesToAdd.length,
aClassName,
theClassNamesToAddArray = [];
for (var i=0;i<iEnd;i++) {
aClassName = classNamesToAdd[i];
if (theClassNames.indexOf(aClassName)===-1) {
theClassNamesToAddArray.push( aClassName );
}
}
oHTMLElement.className = oHTMLElement.className + " " + ((theClassNamesToAddArray.length > 1) ? theClassNamesToAddArray.join(" ") : theClassNamesToAddArray[0]);
}
} else {
oHTMLElement.className = classNameToAdd; // If oHTMLElement did not already have a class name, just add it
}
}
}

////////////////////////////////////////////////////////////////////////////////
//
// hasClassName([object|string] oHTMLElement, string classNameOfInterest)
// Returns a boolean value of if an HTMLElement has the className of interest
// You can pass in the id to an object or the actual object
//
////////////////////////////////////////////////////////////////////////////////
function hasClassName(oHTMLElement, classNameOfInterest) {
return ((" " + oHTMLElement.className + " ").lastIndexOf(" " + classNameOfInterest + " ") > -1);
}
////////////////////////////////////////////////////////////////////////////////
//
// removeClassName([object|string] oHTMLElement, string classNameToRemove)
// Removes classNameToRemove from an HTMLElement, if it exists.
// classNameToRemove can be a space separated list of classNames.
// You can pass in the id to oHTMLElement or the actual object
//
////////////////////////////////////////////////////////////////////////////////
function removeClassName(oHTMLElement, classNameToRemove) {
if (typeof(oHTMLElement)=="string") { oHTMLElement = document.getElementById(oHTMLElement); }
if (oHTMLElement) {
var theClassName = oHTMLElement.className;
if (theClassName && (theClassName.length > 0)) {
var theClassNameArray = theClassName.split(" "),
classNamesToRemove = classNameToRemove.split(" "),
iEnd = theClassNameArray.length,
aClassName,
theNewClassNameArray = [];
for (var i=0;i<iEnd;i++) {
aClassName = theClassNameArray[i];
if (classNamesToRemove.indexOf(aClassName)===-1) {
theNewClassNameArray.push( aClassName );
}
}
switch (true) {
case (theNewClassNameArray.length>1) :
oHTMLElement.className = theNewClassNameArray.join(" ");
break;
case (theNewClassNameArray.length==1) :
oHTMLElement.className = theNewClassNameArray[0];
break;
case (theNewClassNameArray.length==0) :
oHTMLElement.className = "";
break;
}
}
}
}
////////////////////////////////////////////////////////////////////////////////
//
// Array.indexOf() - returns integer index where valueToSearchFor is in an Array
//
////////////////////////////////////////////////////////////////////////////////
if (Array.prototype.indexOf===undefined) {
Array.prototype.indexOf = function( valueToSearchFor ) {
var iEnd = this.length;
var retVal = -1;
for (var i=0;i<iEnd; i++) {
if (this[i] == valueToSearchFor) {
retVal = i;
break;
}
}
return retVal;
};
}


by Shannon Norrell