function imgWidth(){
	var scr = screen.availWidth;
	var air = 8;
	
	if(navigator.appName == "Microsoft Internet Explorer"){
		air = 10;
	}
	
	if(scr < 1400){
        scr = 155+970+((scr-970)/2)-air;
        document.getElementById("contentHeadBackground").style.width = scr+"px";  
		document.getElementById("contentBackground").style.width = scr+"px";  
		document.getElementById("contentFootBackground").style.width = scr+"px";  
	}
}