Determining the operator from a string using javascript

Question

I need your help.

I need to come up with a javascript function that would simply check a string entered into a textbox that would basically determine an SQL operator

example:

var field1 = document.getElementById('field1').value

var field2 = document.getElementById('field2').value

var field3 = document.getElementById('field3').value

function validate(textbox) {

var operator

if ('%' is the first character placed before and after the value) { then operator = LIKE }

else if ('%' is the first character placed before the value) { then operator = LIKE }

else if ('%' is the last character placed after the value) { then operator = LIKE }

else { operator equals "=" } //default

alert(operator)


}

example of function in action:

validate(field1)

Can you provide some sample input strings and expected output? — Vivin Paliath
– Vivin Paliath, Commented May 8, 2013 at 15:45

Annabelle · Accepted Answer · 2013-05-09 16:24:48Z

1

Try the following:

function validate(value) {
  var operator = '=';

  // Check for '%' at the beginning or ending of the value.
  if (value.length > 0 && (value[0] == '%' || value[value.length - 1] == '%')) {
    operator = 'LIKE';
  }

  alert(operator);
}

That said, depending on your target users, it might be easier for them if you included a set of radio button options like "Match beginning", "Match end", and "Match anywhere", instead of requiring them to understand SQL string matching syntax.

For example:

<input id="matchBeginning" type="radio" name="matchMode" value="beginning" />
<label for="matchBeginning">Match beginning of text</label>

<input id="matchEnding" type="radio" name="matchMode" value="ending" />
<label for="matchEnding">Match ending of text</label>

<input id="matchAnywhere" type="radio" name="matchMode" value="anywhere" />
<label for="matchAnywhere">Match anywhere in text</label>

<input id="matchExact" type="radio" name="matchMode" value="exact" />
<label for="matchExact">Match entire text</label>

<input id="field1" type="text" />

You could then pass the value of matchMode (i.e. "beginning", "ending", "anywhere", or "exact") along with the search term up to your server, which would add "%" characters to the search term as dictated by matchMode.

edited May 9, 2013 at 16:24

answered May 8, 2013 at 15:49

Annabelle

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1 Comment

Annabelle Over a year ago

That would probably be due to a missing ")" in the JavaScript example; fixed.

Vivin Paliath · Accepted Answer · 2013-05-08 17:13:26Z

0

You can use regular expressions for this. It looks like if the string contains %, the operator is LIKE. So you can just do this:

var operator = "=";

//If the string starts with a % or ends with a %
//the operator is "LIKE"
if(/^%/.test(str) || /%$/.test(str)) {
   operator = "LIKE";
}

answered May 8, 2013 at 17:13

Vivin Paliath

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