function main_b(idx)
{
var main_b_img1 = document.getElementById('main_b1');
var main_b_img2 = document.getElementById('main_b2');
var main_b_img3 = document.getElementById('main_b3');

 switch(idx) {

	case "1":
 		main_b_img1.src = 'images/index/index_gel_Tmenu_01_ov.gif';
		main_b_img2.src = 'images/index/index_gel_Tmenu_02s.gif';
		main_b_img3.src = 'images/index/index_gel_Tmenu_03.gif';
	break;
	
    case "2":
		main_b_img1.src = 'images/index/index_gel_Tmenu_01.gif';
		main_b_img2.src = 'images/index/index_gel_Tmenu_02_ov.gif';
		main_b_img3.src = 'images/index/index_gel_Tmenu_03s.gif';
	break;
	
    case "3":
		main_b_img1.src = 'images/index/index_gel_Tmenu_01.gif';
		main_b_img2.src = 'images/index/index_gel_Tmenu_02.gif';
		main_b_img3.src = 'images/index/index_gel_Tmenu_03_ov.gif';
	break;
	}
}

// 클릭라인 숨기기
function bluring(){ 
	if(event.srcElement.tagName=="A"||event.srcElement.tagName=="IMG") document.body.focus(); 
}
// 우측마우스 금지
function click() { 
if ((event.button==2) || (event.button==3)) { 
	document.body.disabled=true;
	} 
} 
document.onmousedown=click