Regular Expression Methods, Problem With Escape Characters

Attempting to use javascript's regular expression methods to match a
particular lab number and building which would then be copied to a pair
of textfields, I found that general matching characters needing a
backslash were not recoginized. The following adapted code that finds
a two-button radio selection shows my problem:

function labstat(){
for (i=1; i<3; i++){
if(document.tester.rm_mod[i-1].checked){
var lb = document.tester.elements["lab"+(i)].value;//either
214 or 215*
var bld = document.tester.bldg.value;
if(/*/.test(lb)){ //error:Undetermined comment
// if(/*/.test(lb)){ //error:Syntax error
// if(/5/.test(lb)){ //works to match only 215*
// if(/5*/.test(lb)){ //true for all
// if(/ddd/.test(lb)){ //false for all
document.tester.room1.value = lb;
document.tester.bldg1.value = bld;
}
}
}

It appears that the escaped characters are not recognized, whichever
form of the method is used, i.e var re = /*/; // or = new
RegExp("*");
if(re.test(lb)){
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With the --.match(__) method I have the same problem.