Javascript, change CSS and javascript variable dynamically from form field

Asked by: AtDev

I am trying to dynamically change the CSS element of id "first" according to what is inputed in the field "WIDTH", but I am not having any luck.

I also need it to change the value in a javascript as I have tried to do with "newWidth".

Please help, as I'm loosing my mind as a newbie :-\

<html>
<body>
 
<script language="JavaScript" type="text/javascript">
function changeSize() {
	var widthChange	= document.getElementById("WIDTH");
	document.getElementById('first').style.display == widthCHANGE;
}
</script>
<style type="text/css">
#first {
	width: 150;
}
</style>
 
 
<script language="JavaScript" type="text/javascript">
var newWidth = widthChange;
document.write("The new width is " + newWidth); 
</script>
 
width : <input type="text" id="WIDTH" />
<input type="button" value="change" onclick="javascript:changeSize();" />
 
<img id="first" />
 
</body>
</html>

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few problems with your script

1. Line 6: you are declaring widthChange, but using widthCHANGE elsewhere in the function. javascript is case sensitive
2. Line 7: you have to use style.width instead of style.display to set the width.
3. Line 7: you are using the comparision operator ==, you should use =
4. Line 7: widthCHANGE is a HTML object, you need to use widthCHANGE.value to get the value in the text field
5. Comment out lines 18 & 19

try the code below.. I just performed some cleanup, nothing else is changed

<html>
<body>
 
<script language="JavaScript" type="text/javascript">
function changeSize() {
        var widthChange = document.getElementById("WIDTH");
        document.getElementById('first').style.width = widthChange.value;
}
</script>
<style type="text/css">
#first {
        width: 150;
}
</style>
 
 
<script language="JavaScript" type="text/javascript">
//var newWidth = widthChange;
//document.write("The new width is " + newWidth); 
</script>
width : <input type="text" id="WIDTH" />
<input type="button" value="change" onclick="javascript:changeSize();" />
 
<img id="first" />
 
</body>
</html>

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<html> <head> <style type="text/css"> #first { width: 150; } </style> <script language="JavaScript" type="text/javascript"> function changeSize() { var widthChange = document.getElementById("WIDTH").value; document.getElementById('first').style.width = widthChange + "px"; displaySize(); } function displaySize() { document.getElementById('Message').innerHTML = "The new width is " + document.getElementById('first').width; } </script> </head> <body onload="displaySize();"> width : <input type="text" id="WIDTH" /> <input type="button" value="change" onclick="javascript:changeSize();" /> <img id="first" src="someimage.jpg" /> <div id="Message"></div> </body> </html>

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Javascript, change CSS and javascript variable dynamically from form field

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