div背景色渐变

<script type="text/javascript">

var setGradient = (function(){

var p_dCanvas = document.createElement('canvas');

var p_useCanvas = !!( typeof(p_dCanvas.getContext) == 'function');

var p_dCtx = p_useCanvas?p_dCanvas.getContext('2d'):null;

var p_isIE = false;

try{

p_dCtx.canvas.toDataURL();

}catch(err){

p_useCanvas = false ;

};

if(p_useCanvas){

return function (dEl , sColor1 , sColor2 , bRepeatY ){

if(typeof(dEl) == 'string') dEl = document.getElementById(dEl);

if(!dEl) return false;

var nW = dEl.offsetWidth;

var nH = dEl.offsetHeight;

p_dCanvas.width = nW;

p_dCanvas.height = nH;

var dGradient;

var sRepeat;

if(bRepeatY){

dGradient = p_dCtx.createLinearGradient(0,0,nW,0);

sRepeat = 'repeat-y';

}else{

dGradient = p_dCtx.createLinearGradient(0,0,0,nH);

sRepeat = 'repeat-x';

} 

dGradient.addColorStop(0,sColor1);

dGradient.addColorStop(1,sColor2); 

p_dCtx.fillStyle = dGradient ; 

p_dCtx.fillRect(0,0,nW,nH);

var sDataUrl = p_dCtx.canvas.toDataURL('image/png');

with(dEl.style){

backgroundRepeat = sRepeat;

backgroundImage = 'url(' + sDataUrl + ')';

backgroundColor = sColor2; 

};

};

}else if(p_isIE){

p_dCanvas = p_useCanvas = p_dCtx = null; 

return function (dEl , sColor1 , sColor2 , bRepeatY){

if(typeof(dEl) == 'string') dEl = document.getElementById(dEl);

if(!dEl) return false;

dEl.style.zoom = 1;

var sF = dEl.currentStyle.filter;

dEl.style.filter += ' ' + ['progid:DXImageTransform.Microsoft.gradient( GradientType=', +(!!bRepeatY ),',enabled=true,startColorstr=',sColor1,', endColorstr=',sColor2,')'].join('');

};

}else{

p_dCanvas = p_useCanvas = p_dCtx = null;

return function(dEl , sColor1 , sColor2 ){

if(typeof(dEl) == 'string') dEl = document.getElementById(dEl);

if(!dEl) return false;

with(dEl.style){

backgroundColor = sColor2; 

};

};

}

})();

</script>

 

setGradient('divId','#000000','#ffffff',0);