JavaScript changes the position value to fix the menu after scrolling to the top_javascript skills

Many websites now have such an effect. When the page scrolls to a certain height, the menu bar will be fixed at the top of the page. In fact, it is to change the value of position.
html code:

Copy code The code is as follows:

< ;/div>

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function menuFixed(id){ var obj = document.getElementById(id);
var _getHeight = obj.offsetTop ;

window.onscroll = function(){ changePos(id,_getHeight); } } function changePos(id,height){ var obj = document.getElementById (id); var scrollTop = document.documentElement.scrollTop || document.body.scrollTop;

if(scrollTop obj.style.position = 'relative';
}else{
obj.style.position = 'fixed';
}
}


Finally, it should be noted that this effect is not supported under ie6, because ie6 does not Support position: fixed;
PS: These are some effects I wrote casually based on my knowledge of javascript when I was bored.