日期:2014-05-16  浏览次数:20403 次

JS权威指南中一个改变图片实现checkbox的经典例子。

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<!DOCTYPE html>
<html>
  <head>
    <title>imgex01.html</title>
	
    <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
    <meta http-equiv="description" content="this is my page">
    <meta http-equiv="content-type" content="text/html; charset=UTF-8">
    
    <!--<link rel="stylesheet" type="text/css" href="./styles.css">-->

  </head>
  <script language="JavaScript">
  	function ToggleButton(document,checked,label,onclick){
		if (!ToggleButton.prototype.over) {
			ToggleButton.prototype.over = _ToggleButton_over;
			ToggleButton.prototype.out = _ToggleButton_out;
			ToggleButton.prototype.click = _ToggleButton_click;
			
			ToggleButton.images = new Array(4);
			for (var i = 0; i < 4; i++) {
				ToggleButton.images[i] = new Image(ToggleButton.width, ToggleButton.height);
				ToggleButton.images[i].src = ToggleButton.imagenames[i];
			}
		}
		this.document=document;
		this.checked=checked;
		this.highlighted=false;
		this.onclick=onclick;
		if(typeof this.onclick=="string"){
			this.onclick=new Function("state",this.onclick);
		}
		var index=document.images.length;
		document.write('&nbsp;<a href="about:blank"'+
		'onmouseover="document.images['+index+']._tb.over();return true;"'+
		'onmouseout="document.images['+index+']._tb.out()"'+
		'onclick="document.images['+index+']._tb.click();return false;">');
		document.write('<img src="'+ToggleButton.imagenames[this.checked+0]+'"'+
		'width='+ToggleButton.width+
		'height='+ToggleButton.height+
		'border="0" hspace="0" vspace="0" align="absmiddle">');
		if(label) document.write(label);
		document.write('</a></br>');
		
		this.image=document.images[index];
		this.image._tb=this;
	}
	function _ToggleButton_over(){
		this.image.src=ToggleButton.imagenames[this.checked+2];
		this.highlighted=true;
	}
	function _ToggleButton_out(){
		this.image.src=ToggleButton.imagenames[this.checked+0];
		this.highlighted=false;
	}
	function _ToggleButton_click(){
		this.checked=!this.checked;
		this.image.src=ToggleButton.imagenames[this.checked+this.highlighted*2];
		if(this.onclick) this.onclick(this.checked);
	}
	ToggleButton.imagenames=new Array(4);
	ToggleButton.imagenames[0]="0.png";
	ToggleButton.imagenames[1]="1.png";
	ToggleButton.imagenames[2]="2.png";
	ToggleButton.imagenames[3]="3.png";
	ToggleButton.width=ToggleButton.height=25;
  </script>
  Optional extras:</br>
  <script language="JavaScript">
  	var tb1=new ToggleButton(document,true,"56X Modem");
	var tb2=new ToggleButton(document,false,"Laser Printer",
								function(clicked){
									alert("printer:"+clicked);
								});
	var tb3=new ToggleButton(document,false,"Tape Backup Unit",
								"alert('Tape backup:'+state)");
  </script>
  <body>
  	<form>
  		<input type="button" value="report button states"
		       onclick="alert(tb1.checked+'\n'+tb2.checked+'\n'+tb3.checked)">
		<input type="button" value="reset buttons"
			   onclick="if(tb1.checked) tb1.click();
			   			if(tb2.checked) tb2.click();
			   			if(tb3.checked) tb3.click();"">
  	</form>
  </body>
</html>

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