Setting Div Height

**700lbGorilla** · Jul 31, 2007, 18:17

Is there a way you can find out the height of a div and then set the style height to that value? I'm using a animated collapsing div effect, but it needs to know the height of the div. It works if you set it statically knowing the height ahead of time. But if you load in dynamic text, doesn't work so good. So wondering if there is a way to set it dynamically?

**markusmad** · Jul 31, 2007, 19:59

Does this example work for you?

Also, I noticed that it doesn't calculate borders - at least not in firefox.

Code:

<html>
<head>
<title>test</title>
<script language="javascript" type="text/javascript">
function calculateHeight() {
	var newHeight = document.getElementById('content').clientHeight;
	alert(newHeight);
}
</script>
</head>
<body onLoad="calculateHeight();">
<div id="content">
this<br>
is<br>
dynamic<br>
lol
</div>
</div>
</body>
</html>

**700lbGorilla** · Jul 31, 2007, 20:25

How would I set it though? I'm hoping the script that is collapsing the div even recognizes it. I tried setting it by:

Code:

var newHeight = document.getElementById('testdiv').clientHeight;
document.testdiv.style.height= newHeight;

But that completely breaks the collapsing function.

**markusmad** · Jul 31, 2007, 21:04

Well it returns the height of the div without 'px' at the end, also inside of the script running this animation is where I would calculate the height variable and use it, the height of the div is already set at that value and your script probably will not reflect the change.

I'm not great with javascript but if your animation script requires the height measurement you'll want the variable to be equal to:

newHeight + ' px';

**700lbGorilla** · Aug 1, 2007, 13:13

I thank you for the help, not awesome at JS either. Here is what I'm using, just not sure how to set the height then. The script is called by slideup(divname);

Code:

var timerlen = 5;
var slideAniLen = 250;

var timerID = new Array();
var startTime = new Array();
var obj = new Array();
var endHeight = new Array();
var moving = new Array();
var dir = new Array();

function slidedown(objname){
        if(moving[objname])
                return;

        if(document.getElementById(objname).style.display != "none")
                return; // cannot slide down something that is already visible

        moving[objname] = true;
        dir[objname] = "down";
        startslide(objname);
}

function slideup(objname){
        if(moving[objname])
                return;

        if(document.getElementById(objname).style.display == "none")
                return; // cannot slide up something that is already hidden

        moving[objname] = true;
        dir[objname] = "up";
        startslide(objname);
}

function startslide(objname){
        obj[objname] = document.getElementById(objname);

        endHeight[objname] = parseInt(obj[objname].style.height);
        startTime[objname] = (new Date()).getTime();

        if(dir[objname] == "down"){
                obj[objname].style.height = "1px";
        }

        obj[objname].style.display = "block";

        timerID[objname] = setInterval('slidetick(\'' + objname + '\');',timerlen);
}

function slidetick(objname){
        var elapsed = (new Date()).getTime() - startTime[objname];

        if (elapsed > slideAniLen)
                endSlide(objname)
        else {
                var d =Math.round(elapsed / slideAniLen * endHeight[objname]);
                if(dir[objname] == "up")
                        d = endHeight[objname] - d;

                obj[objname].style.height = d + "px";
        }

        return;
}

function endSlide(objname){
        clearInterval(timerID[objname]);

        if(dir[objname] == "up")
                obj[objname].style.display = "none";

        obj[objname].style.height = endHeight[objname] + "px";

        delete(moving[objname]);
        delete(timerID[objname]);
        delete(startTime[objname]);
        delete(endHeight[objname]);
        delete(obj[objname]);
        delete(dir[objname]);

        return;
}

**markusmad** · Aug 1, 2007, 15:53

Here's my test page I created, html and javascript - I only changed one section of your code "1px" to 1 + 'px':

Code:

<html>
<head>
<title>test</title>
<script language="javascript" type="text/javascript">
var timerlen = 5;
var slideAniLen = 250;

var timerID = new Array();
var startTime = new Array();
var obj = new Array();
var endHeight = new Array();
var moving = new Array();
var dir = new Array();

function slidedown(objname){
        if(moving[objname])
                return;

        if(document.getElementById(objname).style.display != "none")
                return; // cannot slide down something that is already visible

        moving[objname] = true;
        dir[objname] = "down";
        startslide(objname);
}

function slideup(objname){
        if(moving[objname])
                return;

        if(document.getElementById(objname).style.display == "none")
                return; // cannot slide up something that is already hidden

        moving[objname] = true;
        dir[objname] = "up";
        startslide(objname);
}

function startslide(objname){
        obj[objname] = document.getElementById(objname);

        endHeight[objname] = parseInt(obj[objname].style.height);
        startTime[objname] = (new Date()).getTime();

        if(dir[objname] == "down"){
                obj[objname].style.height = 1 + 'px';
        }

        obj[objname].style.display = "block";

        timerID[objname] = setInterval('slidetick(\'' + objname + '\');',timerlen);
}

function slidetick(objname){
        var elapsed = (new Date()).getTime() - startTime[objname];

        if (elapsed > slideAniLen)
                endSlide(objname)
        else {
                var d =Math.round(elapsed / slideAniLen * endHeight[objname]);
                if(dir[objname] == "up")
                        d = endHeight[objname] - d;

                obj[objname].style.height = d + 'px';
        }

        return;
}

function endSlide(objname){
        clearInterval(timerID[objname]);

        if(dir[objname] == "up")
                obj[objname].style.display = "none";

        obj[objname].style.height = endHeight[objname] + "px";

        delete(moving[objname]);
        delete(timerID[objname]);
        delete(startTime[objname]);
        delete(endHeight[objname]);
        delete(obj[objname]);
        delete(dir[objname]);

        return;
}
</script>
</head>

<body>
<div style="height:20px;width:600px;margin:auto;background:blue;" onMouseOver="slidedown('slide2')">
this should slide div 'slide2' down
</div>
<div style="height:200px;width:600px;margin:auto;background:yellow;display:none;" id="slide2" onMouseOut="slideup('slide2')">
new div
</div>
</body>
</html>

Here's the js only

Code:

var timerlen = 5;
var slideAniLen = 250;

var timerID = new Array();
var startTime = new Array();
var obj = new Array();
var endHeight = new Array();
var moving = new Array();
var dir = new Array();

function slidedown(objname){
        if(moving[objname])
                return;

        if(document.getElementById(objname).style.display != "none")
                return; // cannot slide down something that is already visible

        moving[objname] = true;
        dir[objname] = "down";
        startslide(objname);
}

function slideup(objname){
        if(moving[objname])
                return;

        if(document.getElementById(objname).style.display == "none")
                return; // cannot slide up something that is already hidden

        moving[objname] = true;
        dir[objname] = "up";
        startslide(objname);
}

function startslide(objname){
        obj[objname] = document.getElementById(objname);

        endHeight[objname] = parseInt(obj[objname].style.height);
        startTime[objname] = (new Date()).getTime();

        if(dir[objname] == "down"){
                obj[objname].style.height = 1 + 'px';
        }

        obj[objname].style.display = "block";

        timerID[objname] = setInterval('slidetick(\'' + objname + '\');',timerlen);
}

function slidetick(objname){
        var elapsed = (new Date()).getTime() - startTime[objname];

        if (elapsed > slideAniLen)
                endSlide(objname)
        else {
                var d =Math.round(elapsed / slideAniLen * endHeight[objname]);
                if(dir[objname] == "up")
                        d = endHeight[objname] - d;

                obj[objname].style.height = d + 'px';
        }

        return;
}

function endSlide(objname){
        clearInterval(timerID[objname]);

        if(dir[objname] == "up")
                obj[objname].style.display = "none";

        obj[objname].style.height = endHeight[objname] + "px";

        delete(moving[objname]);
        delete(timerID[objname]);
        delete(startTime[objname]);
        delete(endHeight[objname]);
        delete(obj[objname]);
        delete(dir[objname]);

        return;
}

**markusmad** · Aug 1, 2007, 15:54

Oh you know what, I just set the height manually by the div already. <smacks forhead>

**markusmad** · Aug 1, 2007, 16:33

Here's some code I found during a search but I don't understand why offsetHeight is not giving me the div height correctly, showing as 0.

Code:

//Animated Collapsible DIV- Author: Dynamic Drive (http://www.dynamicdrive.com)
//Last updated June 27th, 07'. Added ability for a DIV to be initially expanded.

var uniquepageid=window.location.href.replace("http://"+window.location.hostname, "").replace(/^\//, "") //get current page path and name, used to uniquely identify this page for persistence feature

function animatedcollapse(divId, animatetime, persistexpand, initstate){
	this.divId=divId
	this.divObj=document.getElementById(divId)
	this.divObj.style.overflow="hidden"
	this.timelength=animatetime
	this.initstate=(typeof initstate!="undefined" && initstate=="block")? "block" : "contract"
	this.isExpanded=animatedcollapse.getCookie(uniquepageid+"-"+divId) //"yes" or "no", based on cookie value
	this.contentheight=parseInt(this.divObj.style.height)
	var thisobj=this
	if (isNaN(this.contentheight)){ //if no CSS "height" attribute explicitly defined, get DIV's height on window.load
		animatedcollapse.dotask(window, function(){thisobj._getheight(persistexpand)}, "load")
		if (!persistexpand && this.initstate=="contract" || persistexpand && this.isExpanded!="yes") //Hide DIV (unless div should be expanded by default, OR persistence is enabled and this DIV should be expanded)
			this.divObj.style.visibility="hidden" //hide content (versus collapse) until we can get its height
	}
	else if (!persistexpand && this.initstate=="contract" || persistexpand && this.isExpanded!="yes") //Hide DIV (unless div should be expanded by default, OR persistence is enabled and this DIV should be expanded)
		this.divObj.style.height=0 //just collapse content if CSS "height" attribute available
	if (persistexpand)
		animatedcollapse.dotask(window, function(){animatedcollapse.setCookie(uniquepageid+"-"+thisobj.divId, thisobj.isExpanded)}, "unload")
}

animatedcollapse.prototype._getheight=function(persistexpand){
	this.contentheight=this.divObj.offsetHeight
	if (!persistexpand && this.initstate=="contract" || persistexpand && this.isExpanded!="yes"){ //Hide DIV (unless div should be expanded by default, OR persistence is enabled and this DIV should be expanded)
		this.divObj.style.height=0 //collapse content
		this.divObj.style.visibility="visible"
	}
	else //else if persistence is enabled AND this content should be expanded, define its CSS height value so slideup() has something to work with
		this.divObj.style.height=this.contentheight+"px"
}


animatedcollapse.prototype._slideengine=function(direction){
	var elapsed=new Date().getTime()-this.startTime //get time animation has run
	var thisobj=this
	if (elapsed<this.timelength){ //if time run is less than specified length
		var distancepercent=(direction=="down")? animatedcollapse.curveincrement(elapsed/this.timelength) : 1-animatedcollapse.curveincrement(elapsed/this.timelength)
	this.divObj.style.height=distancepercent * this.contentheight +"px"
	this.runtimer=setTimeout(function(){thisobj._slideengine(direction)}, 10)
	}
	else{ //if animation finished
		this.divObj.style.height=(direction=="down")? this.contentheight+"px" : 0
		this.isExpanded=(direction=="down")? "yes" : "no" //remember whether content is expanded or not
		this.runtimer=null
	}
}


animatedcollapse.prototype.slidedown=function(){
	if (typeof this.runtimer=="undefined" || this.runtimer==null){ //if animation isn't already running or has stopped running
		if (isNaN(this.contentheight)) //if content height not available yet (until window.onload)
			alert("Please wait until document has fully loaded then click again")
		else if (parseInt(this.divObj.style.height)==0){ //if content is collapsed
			this.startTime=new Date().getTime() //Set animation start time
			this._slideengine("down")
		}
	}
}

animatedcollapse.prototype.slideup=function(){
	if (typeof this.runtimer=="undefined" || this.runtimer==null){ //if animation isn't already running or has stopped running
		if (isNaN(this.contentheight)) //if content height not available yet (until window.onload)
			alert("Please wait until document has fully loaded then click again")
		else if (parseInt(this.divObj.style.height)==this.contentheight){ //if content is expanded
			this.startTime=new Date().getTime()
			this._slideengine("up")
		}
	}
}

animatedcollapse.prototype.slideit=function(){
	if (isNaN(this.contentheight)) //if content height not available yet (until window.onload)
		alert("Please wait until document has fully loaded then click again")
	else if (parseInt(this.divObj.style.height)==0)
		this.slidedown()
	else if (parseInt(this.divObj.style.height)==this.contentheight)
		this.slideup()
}

// -------------------------------------------------------------------
// A few utility functions below:
// -------------------------------------------------------------------

animatedcollapse.curveincrement=function(percent){
	return (1-Math.cos(percent*Math.PI)) / 2 //return cos curve based value from a percentage input
}


animatedcollapse.dotask=function(target, functionref, tasktype){ //assign a function to execute to an event handler (ie: onunload)
	var tasktype=(window.addEventListener)? tasktype : "on"+tasktype
	if (target.addEventListener)
		target.addEventListener(tasktype, functionref, false)
	else if (target.attachEvent)
		target.attachEvent(tasktype, functionref)
}

animatedcollapse.getCookie=function(Name){ 
	var re=new RegExp(Name+"=[^;]+", "i"); //construct RE to search for target name/value pair
	if (document.cookie.match(re)) //if cookie found
		return document.cookie.match(re)[0].split("=")[1] //return its value
	return ""
}

animatedcollapse.setCookie=function(name, value, days){
	if (typeof days!="undefined"){ //if set persistent cookie
		var expireDate = new Date()
		var expstring=expireDate.setDate(expireDate.getDate()+days)
		document.cookie = name+"="+value+"; expires="+expireDate.toGMTString()
	}
	else //else if this is a session only cookie
		document.cookie = name+"="+value
}

**700lbGorilla** · Aug 1, 2007, 17:16

I thought maybe it was because the height script was above the div and it was zero at that moment, so set it below the dive and the animation of the up stops and the down just breaks. Frustrating, is there a way to set the inline style directly, but not statically?

**markusmad** · Aug 2, 2007, 08:33

style.display = 'inline'; ?

Yeah this is a pain, nice project =D

Wish someone else would tune in to the discussion I'd like to see the rest of the script made.

**700lbGorilla** · Aug 2, 2007, 10:56

Yeah, I'd think with all the knowledgeable people on here, this wouldn't be a huge problem. But with all the views and no other input, maybe it is, lol. I'll keep trying and thanks for your suggestions.

--Edit--

Well I fixed it, thanks for all your help and suggestions

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