dojo.byId

 

dojo.byId

Status:	Draft
Version:	1.0
Available:	since V?

Contents

• Examples
  • Fade-out a node
  • See Also
  • References

This is a simple alias to ''document.getElementById'', which not only is shorter to write, but fortunately works in all browsers. It turns a domNode reference to some Node byId, or the same node reference if passed a domNode.

1 2	// fetch a node by id="someNode" var node = dojo . byId ( "someNode" );

The node variable is just a native domNode, with properties you can manipulate. The most common, ''innerHTML'':

1 2	// set some node to say "Hello World" dojo . byId ( "someNode" ). innerHTML = "Hello World" ;

If you pass byId a domNode reference, the same node is returned:

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var node = dojo . byId ( "someNode" ); var other = dojo . byId ( node ); console . log ( node == other ); >>> true

If you pass dojo.byId a string, and no domNode is found to match, ''undefined'' or the null object is returned (depending on the browser), which is adequate truthiness to use conditionally:

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var node = dojo . byId ( "fooBar" ); if ( node ){ node . innerHTML = "I was found!" ; } else { console . log ( "no node with id='fooBar' found!" ); }

Most (if not all) functions in Dojo accept either a string or DomNode as a parameter. If passed a string, the function typically calls dojo.byId(), ensuring a domNode is always the object. For instance:

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dojo . style ( dojo . byId ( "foo" ) , "opacity" , 0.5 ); // is identical to: dojo . style ( "foo" , "opacity" , 0.5 );

The latter is preferred, as the call to dojo.byId is made in both cases. The passing of a string ID is consistent throughout the Dojo Toolkit.

JavaScript has a fun convention for conditionals inline. Imagine wanting a domNode reference, and if not present, default to some other node:

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var othernode = dojo . byId ( "fallbackNode" ); var node = dojo . byId ( "missingNode" ) || othernode ; node . innerHTML = "Which one?" ;

Above, if the node id="missingNode" is in fact missing, the logical OR will continue, and use othernode as the value of node.

Examples

Fade-out a node

The following example lets a node by id dissapear from the screen

See Also

• dijit.byId - Accessing a Dijit widget by id.

References

• DOM - Official documentation on the Document Object Model.