how to refer to a form element?
in [JavaScript]
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From: Geoff Cox on 19 Apr 2008 03:32 Hello, I can refer to a form element called value using f.B1.value (where B1 is the name of the input) but need to put this into the more general form to cover f.B2.value, f.B3.value etc I wrote var name='B'+test_num;alert(f.name.value); and this doesn't work. Also tried var name='B'+test_num;alert('f.' + name + '.value'); but this just gives 'f.' + name + '.value' and not the actual value. How do I do this?! Cheers Geoff
From: Tom de Neef on 19 Apr 2008 04:37 "Geoff Cox" <gcox(a)freeuk.notcom> schreef in bericht news:9j7j04p8lsid1npsfnri7d5sk18icrhk75(a)4ax.com... > Hello, > > I can refer to a form element called value using > > f.B1.value (where B1 is the name of the input) > > but need to put this into the more general form to cover > > f.B2.value, f.B3.value etc > > I wrote > > var name='B'+test_num;alert(f.name.value); > > and this doesn't work. > > Also tried > > var name='B'+test_num;alert('f.' + name + '.value'); > > but this just gives 'f.' + name + '.value' and not the actual value. > > How do I do this?! > You can access a propertie via f.B2 but also via f[B2]. In the first case B2 needs to be the name of the property; in the second case it needs to be (an expression that can be evaluated to) a string with the name of the property. So, experiment with f['B'+test_num].value Tom
From: Evertjan. on 19 Apr 2008 04:45 Tom de Neef wrote on 19 apr 2008 in comp.lang.javascript: > "Geoff Cox" <gcox(a)freeuk.notcom> schreef in bericht > news:9j7j04p8lsid1npsfnri7d5sk18icrhk75(a)4ax.com... >> Hello, >> >> I can refer to a form element called value using >> f.B1.value (where B1 is the name of the input) >> but need to put this into the more general form to cover >> f.B2.value, f.B3.value etc >> >> I wrote >> var name='B'+test_num;alert(f.name.value); >> and this doesn't work. >> Also tried >> var name='B'+test_num;alert('f.' + name + '.value'); >> but this just gives 'f.' + name + '.value' and not the actual value. >> How do I do this?! > > You can access a propertie via f.B2 but also via f[B2]. In the first > case B2 needs to be the name of the property; in the second case it > needs to be (an expression that can be evaluated to) a string with the > name of the property. So, experiment with f['B'+test_num].value Beter use the general approach, less error prone, more crossbrowser proof: var n = 2; var result = document.forms['myForm'].elements['B'+n].value; It is a good Idea to read the NG FAQ: <http://jibbering.com/faq/#FAQ4_13> <http://jibbering.com/faq/#FAQ4_25> -- Evertjan. The Netherlands. (Please change the x'es to dots in my emailaddress)
From: Geoff Cox on 19 Apr 2008 04:46 On Sat, 19 Apr 2008 10:37:15 +0200, "Tom de Neef" <tdeneef(a)qolor.nl> wrote: >"Geoff Cox" <gcox(a)freeuk.notcom> schreef in bericht >news:9j7j04p8lsid1npsfnri7d5sk18icrhk75(a)4ax.com... >> Hello, >> >> I can refer to a form element called value using >> >> f.B1.value (where B1 is the name of the input) >> >> but need to put this into the more general form to cover >> >> f.B2.value, f.B3.value etc >> >> I wrote >> >> var name='B'+test_num;alert(f.name.value); >> >> and this doesn't work. >> >> Also tried >> >> var name='B'+test_num;alert('f.' + name + '.value'); >> >> but this just gives 'f.' + name + '.value' and not the actual value. >> >> How do I do this?! >> > >You can access a propertie via f.B2 but also via f[B2]. In the first case B2 >needs to be the name of the property; in the second case it needs to be (an >expression that can be evaluated to) a string with the name of the property. >So, experiment with f['B'+test_num].value >Tom > Many thanks Tom, I was going round in the proverbial circles! Cheers Geoff
From: Lasse Reichstein Nielsen on 19 Apr 2008 05:09 Geoff Cox <gcox(a)freeuk.notcom> writes: > I can refer to a form element called value using > > f.B1.value (where B1 is the name of the input) Maybe you can, maybe you can't, but in any case, you shouldn't. Use the stanard form: document.forms['f'].elements['B1'].value > but need to put this into the more general form to cover > > f.B2.value, f.B3.value etc > > I wrote > > var name='B'+test_num;alert(f.name.value); > > and this doesn't work. As it shouldn't. You are loking up a property called "name", and never referencing the "name" variable. > > Also tried > > var name='B'+test_num;alert('f.' + name + '.value'); Here you do string manipulation, and the result is a string. > but this just gives 'f.' + name + '.value' and not the actual value. It gives the value of the string. > How do I do this?! var name = 'B' + test_num; var value = document.forms['f'].elements[name].value; /L -- Lasse Reichstein Nielsen - lrn(a)hotpop.com DHTML Death Colors: <URL:http://www.infimum.dk/HTML/rasterTriangleDOM.html> 'Faith without judgement merely degrades the spirit divine.'
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