Thursday, February 19, 2009

Dynamic select boxes

These days i was working on a project, where i needed dynamically loading select boxes. I first tried mootools native methods like removing and injecting new option elements in to select element. That worked just fine in FF, but as you expect in IE did not. IE's select box stood unchanged. I remember while ago i have to re-inject the whole select box to see the changes in IE.

According to DOM, there is a better way. HTMLSelectElement support add and remove method that work in all major browsers. So i have implemented three basic methods for mootools Element class.

Element.implement({
	removeAllOptions: function() {
		if(this.get('tag')!='select') return this;
		for(var i=this.options.length-1;i>=0;i--) this.remove(i);
		return this;
	},

	addOption: function(text,value) {
		if(this.get('tag')!='select') return this;
		var optn = new Element('option');
		if(text) optn.text = text;
		if(value) optn.value = value;
		this.options.add(optn);
		return this;
	},

	removeOption: function(prop,value){
		if(this.get('tag')!='select') return this;
		for(var i=this.options.length-1;i>=0;i--) {
			if (prop=='selected' && this.options[i].selected) this.remove(i);
			if (prop=='value' && this.options[i].value==value) this.remove(i);
			if (prop=='text' && this.options[i].text==value) this.remove(i);
			if (prop=='index' && i==value) this.remove(i);
		}
		return this;
	}
});

Methods hopefully already explaining their self.

USAGE

// remove all options or empty select box
$('selectbox').removaAllOptions();

// add options, one after another
$('selectbox').addOption('One',1).addOption('Two',2).addOption('Two',3);

// removing options 
$('selectbox').removeOption('text','One');
$('selectbox').removeOption('value',2);
$('selectbox').removeOption('selected');
$('selectbox').removeOption('index',0);

happy selecting ;)

tags: javascript mootools

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