<body>
<div class="col-lg-1" id="LeftCol" onwheel="Sameheight()"></div>
<div class="col-lg-10" id="MainContent" onwheel="Sameheight()">
<img src ="img.png" alt="" style="height: 500px>
<br>
<img src ="img.png" alt="" style="height: 700px>
<div class="col-lg-1" id="RightCol" onwheel="Sameheight()"></div>
<script type="text/javascript">
function Sameheight(){
var l_height = document.getElementById("LeftCol");
var r_height = document.getElementById("RightCol");
var main = document.getElementById("MainContent");
var L_height = l_height.style.height;
var R_height = r_height.style.height;
var mainn = main.style.height;
if ( mainn > L_height ) {alert();
var difference = mainn - L_height;
L_height += difference;
}if ( L_height > mainn ) {alert();
var difference = L_height - mainn;
mainn += difference;
}if ( mainn > R_height ) {alert();
var difference = mainn - R_height;
R_height += difference;
}if ( R_height > mainn ) {alert();
var difference = R_height - mainn;
mainn += difference;
}if ( R_height > L_height ) {alert();
var difference = R_height - L_height;
L_height += difference;
}if ( L_height > R_height ) {alert();
var difference = L_height - R_height;
R_height += difference;
}
}
</script>
</body>
