IsNumeric? Includes Object.focus() Workaround

I was having trouble getting the object.focus() method in IE and in FF working, so came up with this workaround.

What I wanted to do was check if a textfield was numeric, if not, inform the user then select the text and set the focus back to the field.

Sound simple? object.focus() simply doesn't work in firefox or (I've been informed) IE.

Solution:

Instead of checking when the field losing focus (onblur), check when the next field receives focus (onfocus). Then call a function that gets the element index of the object, and use that index to check the element above it. Difficult to explain.

Here it is...for the textfield you want to check, put this into the next form object after it onfocus="checkNum(this)"

then put this script in the header section...


function checkNum(obj){
var idx;
//get object index
for(idx=0;idx<document.forms[0].elements.length;idx++){
if(document.forms[0].elements[idx].name==obj.name){
break;
};
};
//check for numeric
if (isNaN(document.forms[0].elements[idx-1].value)){
alert('Value must be a number!');

document.forms[0].elements[idx-1].select();
document.forms[0].elements[idx-1].focus();
};
};


But there is one problem!!! As I just found out.

If the next field is a group option, they all have the same name and so this will not work.

for those that do not know, the function isNaN is a js function that is the same as the vbscript equivalent IsNumeric.

isNaN means isNotaNumber.

Hope this helps, I know the focus() failure of JS has been the bane of many coders.